折半查找

#include<stdio.h>
#include<malloc.h>
typedef int ElemType;
typedef struct
{
	ElemType *elem;
	int length;
}SSTable;

void Creat_Seq(SSTable &ST,int n)
{
	int i,temp;
	ST.elem=(ElemType*)malloc(n*sizeof(ElemType));
	if(!(ST).elem)
	{
		printf("ERROR\n");
		return ;
	}
	for(i=0;i<n;i++)
	{
		scanf("%d",&temp);
		ST.elem[i]=temp;
	}
	ST.length=n;
}

int Search_bin(SSTable ST,ElemType key)
{
	int low=0,high,mid;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 -1;
}

int main()
{
	SSTable ST;
	int loc,key,n;
	scanf("%d",&n);
	Creat_Seq(ST,n);
	scanf("%d",&key);
	loc=Search_bin(ST,key);
	if(loc!=-1)
		printf("The element position is %d.\n",loc);
	else
		printf("The element is not exist.\n");
	return 0;
}