#include<iostream>
#include <conio.h>
using namespace std;

int binary(int x[], int n, int key)
{
	int low = 0;
	int hogh = n - 1;

	while (low <= hogh)
	{
		int mid = (low + hogh) / 2;
		if (key == x[mid])
		{
			return mid;
		}
		if (key < x[mid])
		{
			hogh = mid - 1;
		}
		else
		{
			low = mid + 1;
		}

	}
	return -1;
}

int main()
{

	int arr[10] = {1,2,3,4,5,6,7,8,9,10};
	cout << binary(arr, 10, 5);
	_getch();
	return 0;
}