#include <iostream>

using namespace std;

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

int main() {
	int arr[] = {1, 3, 4, 13, 60};
	int n = sizeof(arr) / sizeof(arr[0]);
	int x = 13;
	int result = binarySearch(arr, 0, n-1, x);
	cout << "Index of " << x << " in array is: " << result << endl;
	return 0;
}