折半查找：
代码：
#include<stdio.h>
#include<malloc.h>
typedef struct{
int *elem;
int length;
}sstable;
int searchbin(sstable ST,int key)
{
int low,high,mid;
low=1;high=ST.length;
while(low<=high)
{
mid=(low+high)/2;
if(key==ST.elem[mid]) return(mid);
else if(key<ST.elem[mid])
high=mid-1;
else low=mid+1;
}
return(0);
}
void main()
{
int i,key,location;
sstable ST;
ST.elem=(int*)malloc(ST.length*sizeof(int));
printf("请输入表的长度:\n");
scanf("%d",&ST.length);
printf("请输入待查找表中的元素:\n");
for(i=1;i<=ST.length;i++)
scanf("%d",&ST.elem[i]);
printf("请输入要查找的元素:\n");
scanf("%d",&key);
location=searchbin(ST,key);
printf("要查找的元素的位置为:%d\n",location);
}
运行结果：
见下页。