#include <iostream.h>

int BinarySearch(int [], int, int);

int main()
{
const int NUMEL = 10;
int nums[NUMEL] = {5,10,22,32,45,67,73,98,99,101};
int item, location;

cout << "Enter the item you are searching for: ";
cin >> item;
location = BinarySearch(nums, NUMEL, item);
if (location > -1)
cout << "The item was found at index location "
<< location << endl;
else
cout << "The item was not found in the list\n";

return 0;
}

// this function returns the location of key in the list
// a -1 is returned if the value is not found
int BinarySearch(int list[], int size, int key)
{
int left, right, midpt;

left = 0;
right = size - 1;

while (left <= right)
{
midpt = (int) ((left + right) / 2);
if (key == list[midpt])
{
return midpt;
}
else if (key > list[midpt])
left = midpt + 1;
else
right = midpt - 1;
}

return -1;
}