BINARY SEARCH 

#include <iostream>

int BinarySearch(int arr[], int n, int x)

{

    int low = 0, high = n - 1;

    while (low <= high)

    {

        int mid = (high + low) / 2;

        if (arr[mid] == x)

        {

            return mid;

        }

        else if (arr[mid] > x)

        {

            high = mid - 1;

        }

        else

        {

            low = mid + 1;

        }

    }

    return -1;

}

int main()

{

    int arr[] = {10, 20, 30, 40, 50};

    int size = sizeof(arr) / sizeof(arr[0]);

    std::cout << "The required element is at: " << BinarySearch(arr, size, 50);

}

/*

BINARY SEARCH

-mark the first index as low index and the last index as high index

-In binary search we first find the mid point of the array

-compute [(low + high)/2]

-compare x with mid value

-we come with 3 cases

-case 1: arr[mid] == x; return simply mid value

-case 2: arr[mid] > x;repeat: high = mid - 1

-case 3: arr[mid] < x;repeat: low = mid + 1

*/