BINARY_SEARCH.cpp

#include <stdio.h>

int binarySearch(int arr[], int l, int r, int x)
{
    while (l <= r)
    {
        int m = l + (r-l)/2;

        // Check if x is present at mid 
        if (arr[m] == x)
            return m;

        // If x greater, ignore left half 
        if (arr[m] < x)
            l = m + 1;

        // If x is smaller, ignore right half
        else
            r = m - 1;

    }

    // if we reach here, then element was 
    // not present 
    return -1;
}

int main(void)
{
    int arr[] = {2, 3, 4, 10, 40};
    int n = sizeof(arr)/ sizeof(arr[0]);
    int x = 10;
    int result = binarySearch(arr, 0, n-1, x);
    (result == -1)? printf("Element is not present"
                           " in array")
                  : printf("Element is present at "
                           "index %d", result);
    return 0;
}