有序表查找--二分法查找算法 c++实现

二分法有序表查找：
int binary_search (vector<int>vec ,int key,int low, int high)
{
	int mid;
	while (low <= high)
	{
		mid = (low + high )/ 2;
		if (key < vec[mid])
			high = mid - 1;
		else if (key > vec[mid])
			low  = mid + 1;
		else // key > vec[mid]
			return mid	;
	}
	cout << "no find object value   " << key << ",  between  " << low << "  to  " << high << endl;
	return 0;
}