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));  
}