折半查找（C语言）

折半查找：

#include<stdio.h>
#define NUM 10

int a[]={6,12,28,37,54,65,69,83,90,92};

int BinarySearch(int s[],int n,int key)
{
    int low,high,mid;
    low=0;
    high=n-1;
    while(low<=high)
    {
        mid=(low+high)/2;   //计算中间元素序号
        if(s[mid]==key)     //中间元素与关键字相等
            return mid;
        else if(s[mid]>key)         //中间元素大于关键字
            high=mid-1;
        else
            low=mid+1;
    }
    return -1;      //查找失败返回-1
}

int main()
{
    int key,pos;
    printf("原数据为：");
    for(int i=0;i<NUM;i++)
        printf("%d ",a[i]);
        printf("\n");
    printf("请输入关键字：");
    scanf("%d",&key);
    pos=BinarySearch(a,NUM,key);
    if(pos>=0)
        printf("查找成功！在第%d位！",pos+1);
    else
        printf("查找失败！");
    return 0;

}