折半查找，二分查找

折半查找，二分查找

#include"stdio.h"
int zb_search(int* a, int len, int x);
int main()
{
	int x;
	printf("请输入要查找元素:");
	scanf("%d", &x);
	int a[] = { 3, 5, 10, 22, 24, 29 };
	int len = sizeof(a) / sizeof(int);//计算元素个数
	zb_search(a, len, x);
	return 0;
}
int zb_search(int a[], int len, int x)
{
	int left = 0;//左下标
	int right = len - 1;//右下标
	while (left <= right)
	{
		int mid = (left + right) / 2; //不可以放到while循环外面
		if (x > a[mid])
		{
			left = mid + 1;
		}
		else if (x < a[mid])
		{
			right = mid - 1;
		}
		else
		{
			printf("找到了，它的下标为:%d\n", mid);
			break;
		}
	}
	if (left>right)
	{
		printf("不好意思，找不到!\n");
	}
}