task2.cpp

//Task 2
#include <bits/stdc++.h>
using namespace std;

//Sequential search
int sequential_search(const vector<int>& arr, int target)
{
    for (int i = 0; i < arr.size(); i++)
        if (arr[i] == target){return i;}
    return -1;
}
//Recursive Sequential search
int recursive_sequential_search(const vector<int>& arr, int target, int index = 0)
{
    if (index == arr.size())
        return -1;
    if (arr[index] == target)
        return index;
    return recursive_sequential_search(arr,target,index+1);
}
//Binary_Search
int binary_search(const vector<int>& arr, int target)
{
    int low = 0;
    int high = arr.size()-1;
    while (low <= high)
    {
        int mid = (low + high)/2;
        if (arr[mid] == target)
            return mid;
        else if (arr[mid] < target)
            low = mid + 1;
        else
            high = mid - 1;
    }
    return -1;
}
//Recursive Binary Search
int recursive_binary_search(const vector<int>& arr, int target,int low,int high)
{
    if (low > high)
        return -1;
    int mid = (low + high)/2;
    if (arr[mid] == target)
        return mid;

    if (arr[mid] < target)
        return recursive_binary_search(arr,target,mid+1,high);
    return recursive_binary_search(arr,target,low,mid-1);
}

int main()
{
    cout<<"Enter number of elements in array(Array size must be positive): ";
    int n ;
    cin >> n;
    cout<<"Enter elements: (Elements  must be positive)";
    vector<int> num ;
    for (int i = 0; i < n; i++)
    {
        int value;
        cin >> value;
        num.push_back(value);
    }
    cout<<"Enter target: ";
    int target;
    cin>>target;
    cout << "\nChoose searching method:\n";
    cout << "1 - Sequential Search\n";
    cout << "2 - Recursive Sequential Search\n";
    cout << "3 - Binary Search\n";
    cout << "4 - Recursive Binary Search\n";
    cout << "Enter your choice: ";
    int choice ;
    cin>>choice;
    int result =-1;
    switch (choice) {
    case 1:
        result = sequential_search(num, target);
        break;
    case 2:
        result = recursive_sequential_search(num, target);
        break;
    case 3:
        result = binary_search(num, target);
        break;
    case 4:
        result = recursive_binary_search(num, target, 0, num.size() - 1);
        break;
    default:
        throw invalid_argument("Invalid search method choice.");
    }
   if (result >= 0)
        cout << "Target found at index " << result << endl;
    else
        cout << "Target not found" << endl;
    return 0;
}