Why is this code not printing the value returned by the binarySearch() function?

Question

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

int binarySearch(int [], int, int, int);

int main()
{
    int n, ar[50], givensum;
    cout << "Enter the size of the array: ";
    cin >> n;
    for(int i = 0; i<n; i++)
    {
        cout << "ar[" << i << "] = ";
        cin >> ar[i];
    }
    cout << "Enter the given sum: ";
    cin >> givensum;
    cout << "The closest sum possible is: " << binarySearch(ar, 0, n-1, givensum) << endl;  
}

int binarySearch(int arr[], int l, int r, int key)
{
    int mid = l+(r-l)/2;
    while(l<=r)
    {
        if(arr[mid]==key)
            return arr[mid]+1;
        else if(arr[mid] > key)
            r = mid-1;
        else
            l = mid+1;
    }
    return arr[mid];
}

The code is not printing the value returned by the function. Is the code wrong or the compiler is nuts? I tried storing the return value in another variable but it didn't work out. My interview for Blueflame Labs is scheduled for tomorrow. PLS HELP!!

Answer 1

Your binary search algorithm itself is wrong. It's stuck in an infinite loop.

Corrected code is as follows:

int binarySearch(int arr[], int l, int r, int key)
{
    int mid = l+(r-l)/2;
    while(l<=r)
    {
        if(arr[mid]==key)
            return arr[mid];
        else if(arr[mid] > key)
            r = mid-1;
        else
            l = mid+1;
        mid = l+(r-l)/2;    //update the mid point so you're checking new points
    }
    return arr[mid];
}