c语言二分法

#include <stdio.h>
#include <stdlib.h>

int Search(int *a,int key)
{
int low=0,mid;
int high=20;
while(low<=high)
{
mid=(low+high)/2;
if(key==a[mid]) return mid;    //找到待查元素
else if(key<a[mid]) high=mid-1;//继续在前半区查找
else low=mid+1;                //在后半区查找
}
return 0;                          //未找到
}

void main()
{
int *a,key,i;
int b[10]={0};
a=b;
printf("请输入从大到小的10个整数：\n");
for(i=1;i<=10;i++)
{
scanf("%d",&b[i]);

}
printf("\n");
printf("请输入你要查找的数：\n");
scanf("%d",&key);

if(!Search(a,key)) printf("要查找的数不在目标数组中！\n");
else printf("你要查找的数的序号是：%d \n",Search(a,key));
}