solution-Java-Basics

ArrayDifference.java

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+public class ArrayDifference {
+
+    public static int getDifference(int[] arr) {
+
+        int largest = arr[0];
+        int smallest = arr[0];
+
+
+        for (int i = 1; i < arr.length; i++) {
+            if (arr[i] > largest) {
+                largest = arr[i];
+            }
+            if (arr[i] < smallest) {
+                smallest = arr[i];
+            }
+        }
+
+        return largest - smallest;
+    }
+
+    public static void main(String[] args) {
+        int[] arr1 = {3, 7, 1, 9, 4};
+        int[] arr2 = {-5, -1, -8, -3};
+        int[] arr3 = {42};                  
+        int[] arr4 = {0, 100, -50, 75};
+
+        System.out.println(getDifference(arr1)); // 9 - 1 = 8
+        System.out.println(getDifference(arr2)); // -1 - (-8) = 7
+        System.out.println(getDifference(arr3)); // 42 - 42 = 0
+        System.out.println(getDifference(arr4)); // 100 - (-50) = 150
+    }
+}

Employee.java

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+public class Employee {
+
+    private int id;
+    private String firstName;
+    private String lastName;
+    private String email;
+    private String department;
+    private String jobTitle;
+    private double salary;
+    private int yearsOfExperience;
+    private boolean isActive;
+
+    public Employee(int id, String firstName, String lastName,
+            String email, String department,
+            String jobTitle, double salary, int yearsOfExperience) {
+
+        this.id = id;
+        this.firstName = firstName;
+        this.lastName = lastName;
+        this.email = email;
+        this.department = department;
+        this.jobTitle = jobTitle;
+        this.salary = salary;
+        this.yearsOfExperience = yearsOfExperience;
+        this.isActive = true; // new employees are active by default
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getFirstName() {
+        return firstName;
+    }
+
+    public void setFirstName(String firstName) {
+        this.firstName = firstName;
+    }
+
+    public String getLastName() {
+        return lastName;
+    }
+
+    public void setLastName(String lastName) {
+        this.lastName = lastName;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+
+    public String getDepartment() {
+        return department;
+    }
+
+    public void setDepartment(String department) {
+        this.department = department;
+    }
+
+    public String getJobTitle() {
+        return jobTitle;
+    }
+
+    public void setJobTitle(String jobTitle) {
+        this.jobTitle = jobTitle;
+    }
+
+    public double getSalary() {
+        return salary;
+    }
+
+    public void setSalary(double salary) {
+        if (salary < 0) {
+            System.out.println("Salary cannot be negative. No changes made.");
+            return;
+        }
+        this.salary = salary;
+    }
+
+    public int getYearsOfExperience() {
+        return yearsOfExperience;
+    }
+
+    public void setYearsOfExperience(int yearsOfExperience) {
+        if (yearsOfExperience < 0) {
+            System.out.println("Years of experience cannot be negative. No changes made.");
+            return;
+        }
+        this.yearsOfExperience = yearsOfExperience;
+    }
+
+    public boolean isActive() {
+        return isActive;
+    }
+
+    public void setActive(boolean isActive) {
+        this.isActive = isActive;
+    }
+
+    // Returns the employee's full name
+    public String getFullName() {
+        return firstName + " " + lastName;
+    }
+
+    // Applies a raise by percentage (e.g. 10 = 10% raise)
+    public void applyRaise(double percentage) {
+        if (percentage <= 0) {
+            System.out.println("Raise percentage must be positive.");
+            return;
+        }
+        double raise = salary * (percentage / 100);
+        salary += raise;
+        System.out.printf("Raise applied! " + getFullName() + "'s new salary: " + salary);
+    }
+
+    // Transfers the employee to a new department with an optional new job title
+    public void transferTo(String newDepartment, String newJobTitle) {
+        System.out.printf(
+                getFullName() + " transferred from " + department + " to " + newDepartment + " as " + newJobTitle);
+        this.department = newDepartment;
+        this.jobTitle = newJobTitle;
+    }
+
+    // Marks the employee as inactive (resigned / terminated)
+    public void terminate() {
+        this.isActive = false;
+        System.out.println(getFullName() + " has been marked as inactive.");
+    }
+
+    // Prints a formatted summary of the employee to the console
+    public void printProfile() {
+        System.out.println("         Employee Profile         ");
+        System.out.println("ID              : " + id);
+        System.out.println("Name            : " + getFullName());
+        System.out.println("Email           : " + email);
+        System.out.println("Department      : " + department);
+        System.out.println("Job Title       : " + jobTitle);
+        System.out.println("Salary          : " + salary);
+        System.out.println("Experience      : " + yearsOfExperience + " year(s)");
+        System.out.println("Status          : " + (isActive ? "Active" : "Inactive"));
+    }
+
+    public static void main(String[] args) {
+
+        // Create an employee
+        Employee emp = new Employee(
+                101, "Alice", "Johnson", "alice@company.com",
+                "Engineering", "Software Developer", 75000.00, 3);
+
+        // Print initial profile
+        emp.printProfile();
+
+        // Apply a 10% raise
+        emp.applyRaise(10);
+
+        // Transfer to a new department
+        emp.transferTo("Product", "Product Engineer");
+
+        // Try setting an invalid salary
+        emp.setSalary(-5000);
+
+        // Print updated profile
+        emp.printProfile();
+
+        // Terminate the employee
+        emp.terminate();
+        System.out.println("Is Active: " + emp.isActive());
+    }
+}

Intern.java

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+public class Intern extends Employee {
+
+    public static final double MAX_SALARY = 20000.00;
+    private String university;
+    private String internshipField;
+    private int durationMonths;
+
+    public Intern(int id, String firstName, String lastName,
+            String email, String department,
+            double salary, String university,
+            String internshipField, int durationMonths) {
+
+        // Pass "Intern" as the fixed job title up to Employee
+        super(id, firstName, lastName, email, department,
+                "Intern", validateSalary(salary), 0);
+
+        this.university = university;
+        this.internshipField = internshipField;
+        this.durationMonths = durationMonths;
+    }
+
+    private static double validateSalary(double salary) {
+        if (salary > MAX_SALARY) {
+
+            System.out.println("Warning: Salary " + salary + " cannot exceed intern limit. Salary has been capped at "
+                    + MAX_SALARY + ".");
+            return MAX_SALARY;
+        }
+        if (salary < 0) {
+            System.out.println("Warning: Salary cannot be negative. ");
+            return 0;
+        }
+        return salary;
+    }
+
+    @Override
+    public void setSalary(double salary) {
+        super.setSalary(validateSalary(salary));
+    }
+
+    @Override
+    public void applyRaise(double percentage) {
+        if (percentage <= 0) {
+            System.out.println("Raise percentage must be positive.");
+            return;
+        }
+        double raisedSalary = getSalary() * (1 + percentage / 100);
+        if (raisedSalary > MAX_SALARY) {
+            super.setSalary(MAX_SALARY);
+            System.out.println(
+                    "Raise applied but capped at intern limit. " + getFullName() + "'s new salary: " + MAX_SALARY);
+        } else {
+            super.setSalary(raisedSalary);
+            System.out.println("Raise applied! " + getFullName() + "'s new salary: " + getSalary());
+        }
+    }
+
+    public String getUniversity() {
+        return university;
+    }
+
+    public void setUniversity(String university) {
+        this.university = university;
+    }
+
+    public String getInternshipField() {
+        return internshipField;
+    }
+
+    public void setInternshipField(String internshipField) {
+        this.internshipField = internshipField;
+    }
+
+    public int getDurationMonths() {
+        return durationMonths;
+    }
+
+    public void setDurationMonths(int durationMonths) {
+        if (durationMonths <= 0) {
+            System.out.println("Duration must be at least 1 month. No changes made.");
+            return;
+        }
+        this.durationMonths = durationMonths;
+    }
+
+    @Override
+    public void printProfile() {
+        System.out.println("          Intern Profile          ");
+        System.out.println("ID              : " + getId());
+        System.out.println("Name            : " + getFullName());
+        System.out.println("Email           : " + getEmail());
+        System.out.println("Department      : " + getDepartment());
+        System.out.println("Field           : " + internshipField);
+        System.out.println("University      : " + university);
+        System.out.println("Duration        : " + durationMonths + " month(s)");
+        System.out.println("Salary          : $" + getSalary());
+        System.out.println("Status          : " + (isActive() ? "Active" : "Inactive"));
+        System.out.println("===================================");
+    }
+
+    public static void main(String[] args) {
+
+        System.out.println(">>> Creating intern with valid salary ($15000):");
+        Intern intern1 = new Intern(
+                201, "Bob", "Smith", "bob@company.com",
+                "Engineering", 15000,
+                "TU Munich", "Software Engineering", 6);
+        intern1.printProfile();
+
+        System.out.println(">>> Creating intern with salary ABOVE the limit ($25000):");
+        Intern intern2 = new Intern(
+                202, "Sara", "Lee", "sara@company.com",
+                "Marketing", 25000,
+                "LMU Munich", "Digital Marketing", 3);
+        intern2.printProfile();
+
+        System.out.println(">>> Trying to update salary above limit via setSalary():");
+        intern1.setSalary(22000);
+        System.out.println("Salary after update: $" + intern1.getSalary());
+
+        System.out.println(">>> Applying a raise that stays within the limit:");
+        intern1.setSalary(15000);
+        intern1.applyRaise(10); // 15000 + 10% = 16500 → within limit
+
+        System.out.println(">>> Applying a raise that exceeds the limit:");
+        intern1.setSalary(19000);
+        intern1.applyRaise(20); // 19000 + 20% = 22800 → capped at 20000
+
+        System.out.println(">>> Creating intern with negative salary:");
+        Intern intern3 = new Intern(
+                203, "Tom", "Baker", "tom@company.com",
+                "HR", -5000,
+                "University of Augsburg", "HR Management", 4);
+        System.out.println("Salary after creation: $" + intern3.getSalary());
+    }
+}

Main.java

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+public class Main {
+
+    public static void main(String[] args) {
+
+        // Create an array of 10 Employees
+        Employee[] employees = new Employee[10];
+
+        employees[0] = new Employee(101, "Alice",   "Johnson", "alice.johnson@company.com",   "Engineering",  "Software Developer",    75000.00, 3);
+        employees[1] = new Employee(102, "Bob",     "Smith",   "bob.smith@company.com",       "Marketing",    "Marketing Manager",     65000.00, 7);
+        employees[2] = new Employee(103, "Clara",   "Davis",   "clara.davis@company.com",     "HR",           "HR Specialist",         55000.00, 2);
+        employees[3] = new Employee(104, "David",   "Wilson",  "david.wilson@company.com",    "Finance",      "Financial Analyst",     70000.00, 5);
+        employees[4] = new Employee(105, "Eva",     "Martinez","eva.martinez@company.com",    "Engineering",  "DevOps Engineer",       80000.00, 6);
+        employees[5] = new Employee(106, "Frank",   "Brown",   "frank.brown@company.com",     "Sales",        "Sales Representative",  48000.00, 1);
+        employees[6] = new Employee(107, "Grace",   "Taylor",  "grace.taylor@company.com",    "Design",       "UX Designer",           62000.00, 4);
+        employees[7] = new Employee(108, "Henry",   "Anderson","henry.anderson@company.com",  "Engineering",  "Backend Developer",     78000.00, 8);
+        employees[8] = new Employee(109, "Isla",    "Thomas",  "isla.thomas@company.com",     "Legal",        "Legal Counsel",         90000.00, 10);
+        employees[9] = new Employee(110, "James",   "Jackson", "james.jackson@company.com",   "Operations",   "Operations Manager",    68000.00, 9);
+
+        // Print all employee profiles
+        for (Employee emp : employees) {
+            emp.printProfile();
+            System.out.println();
+        }
+
+        // Summary
+        System.out.println("Total employees: " + employees.length);
+    }
+}