diff --git a/exercises/concept/doctor-data/test/catch.hpp b/exercises/concept/doctor-data/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/concept/doctor-data/test/catch.hpp
+++ b/exercises/concept/doctor-data/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/concept/election-day/test/catch.hpp b/exercises/concept/election-day/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/concept/election-day/test/catch.hpp
+++ b/exercises/concept/election-day/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/concept/ellens-alien-game/test/catch.hpp b/exercises/concept/ellens-alien-game/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/concept/ellens-alien-game/test/catch.hpp
+++ b/exercises/concept/ellens-alien-game/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/concept/freelancer-rates/test/catch.hpp b/exercises/concept/freelancer-rates/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/concept/freelancer-rates/test/catch.hpp
+++ b/exercises/concept/freelancer-rates/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/concept/interest-is-interesting/test/catch.hpp b/exercises/concept/interest-is-interesting/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/concept/interest-is-interesting/test/catch.hpp
+++ b/exercises/concept/interest-is-interesting/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/concept/lasagna-master/test/catch.hpp b/exercises/concept/lasagna-master/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/concept/lasagna-master/test/catch.hpp
+++ b/exercises/concept/lasagna-master/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/concept/lasagna/test/catch.hpp b/exercises/concept/lasagna/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/concept/lasagna/test/catch.hpp
+++ b/exercises/concept/lasagna/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/concept/last-will/test/catch.hpp b/exercises/concept/last-will/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/concept/last-will/test/catch.hpp
+++ b/exercises/concept/last-will/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/concept/log-levels/test/catch.hpp b/exercises/concept/log-levels/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/concept/log-levels/test/catch.hpp
+++ b/exercises/concept/log-levels/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/concept/making-the-grade/test/catch.hpp b/exercises/concept/making-the-grade/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/concept/making-the-grade/test/catch.hpp
+++ b/exercises/concept/making-the-grade/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/concept/pacman-rules/test/catch.hpp b/exercises/concept/pacman-rules/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/concept/pacman-rules/test/catch.hpp
+++ b/exercises/concept/pacman-rules/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/concept/power-of-troy/test/catch.hpp b/exercises/concept/power-of-troy/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/concept/power-of-troy/test/catch.hpp
+++ b/exercises/concept/power-of-troy/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/concept/speedywagon/test/catch.hpp b/exercises/concept/speedywagon/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/concept/speedywagon/test/catch.hpp
+++ b/exercises/concept/speedywagon/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/concept/troll-the-trolls/test/catch.hpp b/exercises/concept/troll-the-trolls/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/concept/troll-the-trolls/test/catch.hpp
+++ b/exercises/concept/troll-the-trolls/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/concept/vehicle-purchase/test/catch.hpp b/exercises/concept/vehicle-purchase/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/concept/vehicle-purchase/test/catch.hpp
+++ b/exercises/concept/vehicle-purchase/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/acronym/test/catch.hpp b/exercises/practice/acronym/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/acronym/test/catch.hpp
+++ b/exercises/practice/acronym/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/affine-cipher/test/catch.hpp b/exercises/practice/affine-cipher/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/affine-cipher/test/catch.hpp
+++ b/exercises/practice/affine-cipher/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/all-your-base/test/catch.hpp b/exercises/practice/all-your-base/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/all-your-base/test/catch.hpp
+++ b/exercises/practice/all-your-base/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/allergies/test/catch.hpp b/exercises/practice/allergies/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/allergies/test/catch.hpp
+++ b/exercises/practice/allergies/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/alphametics/test/catch.hpp b/exercises/practice/alphametics/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/alphametics/test/catch.hpp
+++ b/exercises/practice/alphametics/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/anagram/test/catch.hpp b/exercises/practice/anagram/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/anagram/test/catch.hpp
+++ b/exercises/practice/anagram/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/armstrong-numbers/test/catch.hpp b/exercises/practice/armstrong-numbers/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/armstrong-numbers/test/catch.hpp
+++ b/exercises/practice/armstrong-numbers/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/atbash-cipher/test/catch.hpp b/exercises/practice/atbash-cipher/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/atbash-cipher/test/catch.hpp
+++ b/exercises/practice/atbash-cipher/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/bank-account/test/catch.hpp b/exercises/practice/bank-account/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/bank-account/test/catch.hpp
+++ b/exercises/practice/bank-account/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/beer-song/test/catch.hpp b/exercises/practice/beer-song/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/beer-song/test/catch.hpp
+++ b/exercises/practice/beer-song/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/binary-search-tree/test/catch.hpp b/exercises/practice/binary-search-tree/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/binary-search-tree/test/catch.hpp
+++ b/exercises/practice/binary-search-tree/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/binary-search/test/catch.hpp b/exercises/practice/binary-search/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/binary-search/test/catch.hpp
+++ b/exercises/practice/binary-search/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/binary/test/catch.hpp b/exercises/practice/binary/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/binary/test/catch.hpp
+++ b/exercises/practice/binary/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/bob/test/catch.hpp b/exercises/practice/bob/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/bob/test/catch.hpp
+++ b/exercises/practice/bob/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/circular-buffer/test/catch.hpp b/exercises/practice/circular-buffer/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/circular-buffer/test/catch.hpp
+++ b/exercises/practice/circular-buffer/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/clock/test/catch.hpp b/exercises/practice/clock/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/clock/test/catch.hpp
+++ b/exercises/practice/clock/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/collatz-conjecture/test/catch.hpp b/exercises/practice/collatz-conjecture/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/collatz-conjecture/test/catch.hpp
+++ b/exercises/practice/collatz-conjecture/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/complex-numbers/test/catch_amalgamated.cpp b/exercises/practice/complex-numbers/test/catch_amalgamated.cpp
index eba3f00ac..b48af9055 100644
--- a/exercises/practice/complex-numbers/test/catch_amalgamated.cpp
+++ b/exercises/practice/complex-numbers/test/catch_amalgamated.cpp
@@ -468,10 +468,10 @@ namespace Catch {
     }
 
 namespace literals {
-    Approx operator "" _a(long double val) {
+    Approx operator ""_a(long double val) {
         return Approx(val);
     }
-    Approx operator "" _a(unsigned long long val) {
+    Approx operator ""_a(unsigned long long val) {
         return Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/crypto-square/test/catch.hpp b/exercises/practice/crypto-square/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/crypto-square/test/catch.hpp
+++ b/exercises/practice/crypto-square/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/darts/test/catch.hpp b/exercises/practice/darts/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/darts/test/catch.hpp
+++ b/exercises/practice/darts/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/diamond/test/catch.hpp b/exercises/practice/diamond/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/diamond/test/catch.hpp
+++ b/exercises/practice/diamond/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/difference-of-squares/test/catch.hpp b/exercises/practice/difference-of-squares/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/difference-of-squares/test/catch.hpp
+++ b/exercises/practice/difference-of-squares/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/dnd-character/test/catch.hpp b/exercises/practice/dnd-character/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/dnd-character/test/catch.hpp
+++ b/exercises/practice/dnd-character/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/eliuds-eggs/test/catch.hpp b/exercises/practice/eliuds-eggs/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/eliuds-eggs/test/catch.hpp
+++ b/exercises/practice/eliuds-eggs/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/etl/test/catch.hpp b/exercises/practice/etl/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/etl/test/catch.hpp
+++ b/exercises/practice/etl/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/flower-field/test/catch.hpp b/exercises/practice/flower-field/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/flower-field/test/catch.hpp
+++ b/exercises/practice/flower-field/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/food-chain/test/catch.hpp b/exercises/practice/food-chain/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/food-chain/test/catch.hpp
+++ b/exercises/practice/food-chain/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/gigasecond/test/catch.hpp b/exercises/practice/gigasecond/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/gigasecond/test/catch.hpp
+++ b/exercises/practice/gigasecond/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/grade-school/test/catch.hpp b/exercises/practice/grade-school/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/grade-school/test/catch.hpp
+++ b/exercises/practice/grade-school/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/grains/test/catch.hpp b/exercises/practice/grains/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/grains/test/catch.hpp
+++ b/exercises/practice/grains/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/hamming/test/catch.hpp b/exercises/practice/hamming/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/hamming/test/catch.hpp
+++ b/exercises/practice/hamming/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/hello-world/test/catch.hpp b/exercises/practice/hello-world/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/hello-world/test/catch.hpp
+++ b/exercises/practice/hello-world/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/hexadecimal/test/catch.hpp b/exercises/practice/hexadecimal/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/hexadecimal/test/catch.hpp
+++ b/exercises/practice/hexadecimal/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/high-scores/test/catch.hpp b/exercises/practice/high-scores/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/high-scores/test/catch.hpp
+++ b/exercises/practice/high-scores/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/isbn-verifier/test/catch.hpp b/exercises/practice/isbn-verifier/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/isbn-verifier/test/catch.hpp
+++ b/exercises/practice/isbn-verifier/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/isogram/test/catch.hpp b/exercises/practice/isogram/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/isogram/test/catch.hpp
+++ b/exercises/practice/isogram/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/kindergarten-garden/test/catch.hpp b/exercises/practice/kindergarten-garden/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/kindergarten-garden/test/catch.hpp
+++ b/exercises/practice/kindergarten-garden/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/knapsack/test/catch.hpp b/exercises/practice/knapsack/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/knapsack/test/catch.hpp
+++ b/exercises/practice/knapsack/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/largest-series-product/test/catch.hpp b/exercises/practice/largest-series-product/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/largest-series-product/test/catch.hpp
+++ b/exercises/practice/largest-series-product/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/leap/test/catch.hpp b/exercises/practice/leap/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/leap/test/catch.hpp
+++ b/exercises/practice/leap/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/linked-list/test/catch.hpp b/exercises/practice/linked-list/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/linked-list/test/catch.hpp
+++ b/exercises/practice/linked-list/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/list-ops/test/catch.hpp b/exercises/practice/list-ops/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/list-ops/test/catch.hpp
+++ b/exercises/practice/list-ops/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/luhn/test/catch.hpp b/exercises/practice/luhn/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/luhn/test/catch.hpp
+++ b/exercises/practice/luhn/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/matching-brackets/test/catch.hpp b/exercises/practice/matching-brackets/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/matching-brackets/test/catch.hpp
+++ b/exercises/practice/matching-brackets/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/meetup/test/catch.hpp b/exercises/practice/meetup/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/meetup/test/catch.hpp
+++ b/exercises/practice/meetup/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/minesweeper/test/catch.hpp b/exercises/practice/minesweeper/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/minesweeper/test/catch.hpp
+++ b/exercises/practice/minesweeper/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/nth-prime/test/catch.hpp b/exercises/practice/nth-prime/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/nth-prime/test/catch.hpp
+++ b/exercises/practice/nth-prime/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/nucleotide-count/test/catch.hpp b/exercises/practice/nucleotide-count/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/nucleotide-count/test/catch.hpp
+++ b/exercises/practice/nucleotide-count/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/pangram/test/catch.hpp b/exercises/practice/pangram/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/pangram/test/catch.hpp
+++ b/exercises/practice/pangram/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/parallel-letter-frequency/test/catch.hpp b/exercises/practice/parallel-letter-frequency/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/parallel-letter-frequency/test/catch.hpp
+++ b/exercises/practice/parallel-letter-frequency/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/pascals-triangle/test/catch.hpp b/exercises/practice/pascals-triangle/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/pascals-triangle/test/catch.hpp
+++ b/exercises/practice/pascals-triangle/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/perfect-numbers/test/catch.hpp b/exercises/practice/perfect-numbers/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/perfect-numbers/test/catch.hpp
+++ b/exercises/practice/perfect-numbers/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/phone-number/test/catch.hpp b/exercises/practice/phone-number/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/phone-number/test/catch.hpp
+++ b/exercises/practice/phone-number/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/pig-latin/test/catch.hpp b/exercises/practice/pig-latin/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/pig-latin/test/catch.hpp
+++ b/exercises/practice/pig-latin/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/prime-factors/test/catch.hpp b/exercises/practice/prime-factors/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/prime-factors/test/catch.hpp
+++ b/exercises/practice/prime-factors/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/protein-translation/test/catch.hpp b/exercises/practice/protein-translation/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/protein-translation/test/catch.hpp
+++ b/exercises/practice/protein-translation/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/queen-attack/test/catch.hpp b/exercises/practice/queen-attack/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/queen-attack/test/catch.hpp
+++ b/exercises/practice/queen-attack/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/rail-fence-cipher/test/catch.hpp b/exercises/practice/rail-fence-cipher/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/rail-fence-cipher/test/catch.hpp
+++ b/exercises/practice/rail-fence-cipher/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/raindrops/test/catch.hpp b/exercises/practice/raindrops/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/raindrops/test/catch.hpp
+++ b/exercises/practice/raindrops/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/resistor-color-duo/test/catch.hpp b/exercises/practice/resistor-color-duo/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/resistor-color-duo/test/catch.hpp
+++ b/exercises/practice/resistor-color-duo/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/resistor-color/test/catch.hpp b/exercises/practice/resistor-color/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/resistor-color/test/catch.hpp
+++ b/exercises/practice/resistor-color/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/reverse-string/test/catch.hpp b/exercises/practice/reverse-string/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/reverse-string/test/catch.hpp
+++ b/exercises/practice/reverse-string/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/rna-transcription/test/catch.hpp b/exercises/practice/rna-transcription/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/rna-transcription/test/catch.hpp
+++ b/exercises/practice/rna-transcription/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/robot-name/test/catch.hpp b/exercises/practice/robot-name/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/robot-name/test/catch.hpp
+++ b/exercises/practice/robot-name/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/robot-simulator/test/catch.hpp b/exercises/practice/robot-simulator/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/robot-simulator/test/catch.hpp
+++ b/exercises/practice/robot-simulator/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/roman-numerals/test/catch.hpp b/exercises/practice/roman-numerals/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/roman-numerals/test/catch.hpp
+++ b/exercises/practice/roman-numerals/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/rotational-cipher/test/catch.hpp b/exercises/practice/rotational-cipher/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/rotational-cipher/test/catch.hpp
+++ b/exercises/practice/rotational-cipher/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/run-length-encoding/test/catch.hpp b/exercises/practice/run-length-encoding/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/run-length-encoding/test/catch.hpp
+++ b/exercises/practice/run-length-encoding/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/say/test/catch.hpp b/exercises/practice/say/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/say/test/catch.hpp
+++ b/exercises/practice/say/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/scrabble-score/test/catch.hpp b/exercises/practice/scrabble-score/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/scrabble-score/test/catch.hpp
+++ b/exercises/practice/scrabble-score/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/secret-handshake/test/catch.hpp b/exercises/practice/secret-handshake/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/secret-handshake/test/catch.hpp
+++ b/exercises/practice/secret-handshake/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/series/test/catch.hpp b/exercises/practice/series/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/series/test/catch.hpp
+++ b/exercises/practice/series/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/sieve/test/catch.hpp b/exercises/practice/sieve/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/sieve/test/catch.hpp
+++ b/exercises/practice/sieve/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/simple-linked-list/test/catch.hpp b/exercises/practice/simple-linked-list/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/simple-linked-list/test/catch.hpp
+++ b/exercises/practice/simple-linked-list/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/space-age/test/catch.hpp b/exercises/practice/space-age/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/space-age/test/catch.hpp
+++ b/exercises/practice/space-age/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/spiral-matrix/test/catch.hpp b/exercises/practice/spiral-matrix/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/spiral-matrix/test/catch.hpp
+++ b/exercises/practice/spiral-matrix/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/sublist/test/catch.hpp b/exercises/practice/sublist/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/sublist/test/catch.hpp
+++ b/exercises/practice/sublist/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/sum-of-multiples/test/catch.hpp b/exercises/practice/sum-of-multiples/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/sum-of-multiples/test/catch.hpp
+++ b/exercises/practice/sum-of-multiples/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/triangle/test/catch.hpp b/exercises/practice/triangle/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/triangle/test/catch.hpp
+++ b/exercises/practice/triangle/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/trinary/test/catch.hpp b/exercises/practice/trinary/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/trinary/test/catch.hpp
+++ b/exercises/practice/trinary/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/twelve-days/test/catch.hpp b/exercises/practice/twelve-days/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/twelve-days/test/catch.hpp
+++ b/exercises/practice/twelve-days/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/two-bucket/test/catch.hpp b/exercises/practice/two-bucket/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/two-bucket/test/catch.hpp
+++ b/exercises/practice/two-bucket/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/two-fer/test/catch.hpp b/exercises/practice/two-fer/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/two-fer/test/catch.hpp
+++ b/exercises/practice/two-fer/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/word-count/test/catch.hpp b/exercises/practice/word-count/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/word-count/test/catch.hpp
+++ b/exercises/practice/word-count/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/yacht/test/catch.hpp b/exercises/practice/yacht/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/yacht/test/catch.hpp
+++ b/exercises/practice/yacht/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/exercises/practice/zebra-puzzle/test/catch.hpp b/exercises/practice/zebra-puzzle/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/exercises/practice/zebra-puzzle/test/catch.hpp
+++ b/exercises/practice/zebra-puzzle/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals
diff --git a/test/catch.hpp b/test/catch.hpp
index 36eaeb27f..ff40b4fd6 100644
--- a/test/catch.hpp
+++ b/test/catch.hpp
@@ -3175,8 +3175,8 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val);
-    Detail::Approx operator "" _a(unsigned long long val);
+    Detail::Approx operator ""_a(long double val);
+    Detail::Approx operator ""_a(unsigned long long val);
 } // end namespace literals
 
 template<>
@@ -7911,10 +7911,10 @@ namespace Detail {
 } // end namespace Detail
 
 namespace literals {
-    Detail::Approx operator "" _a(long double val) {
+    Detail::Approx operator ""_a(long double val) {
         return Detail::Approx(val);
     }
-    Detail::Approx operator "" _a(unsigned long long val) {
+    Detail::Approx operator ""_a(unsigned long long val) {
         return Detail::Approx(val);
     }
 } // end namespace literals