Binary search for any data type using template for C++. Does not return true/false, but instead returns index of element searching for. Not entirely sure if it works, don't care enough to find out.

BinarySearch.h

#ifndef BINARYSEARCH_H
#define BINARYSEARCH_H

template<typename T>
int binarySearch(T list[], T key, int size) {
	int low = 0;
	int high = size - 1;
	
	while (high >= low) {
		int mid = (low + high) / 2;
		if (key < list[mid])
			high = mid - 1;
		else if (key == list[mid])
			return mid;
		else
			low = mid + 1;
	}
	
	return -low - 1; // -low - 1?
}

#endif

main.cpp

#include "BinarySearch.h"
#include <iostream>
using namespace std;

int main () {
	
	int list[] = {1, 5, 4, 3, 2, 7, 9};
	
	// output should be index of '5', or '1'
	cout << "Index of '5' is " << binarySearch(list, 5, 7) << endl;
	
	return 0;
}