二分搜索，正确性未知……

gistfile1.c

typedef int type;

int my_binary_search(type *array, int begin, int end, type key) {
  int mid = 0;
	if(array == NULL || begin > end || begin < 0)
		return -1;
	else 
		mid = begin + ((end - begin) >> 2);

	if(array[mid] == key)
		return mid;
	else if(array[mid] > key && mid > begin)
		return my_binary_search(array, begin, mid - 1, key);
	else if(array[mid] < key && mid < end)
		return my_binary_search(array, mid + 1, end, key);
	else 
		return -1;
}