Binary Search

int binary_search(int A[], int beg, int end, int target)
{
	int i = beg, j = end;
	while (i < j)
	{
		int mid = (i + j) / 2;
		if (target < A[mid])
			j = mid;
		else if (target > A[mid])
			i = mid + 1;
		else
			return mid;
	}
	return -1;
}