#include 
     
      using namespace std;int a[5]={1,2,3,4,5};int Bsearch(int x, int left,int right ){	if(left<=right)	{		int m=(left+right)/2;		if(x
      
       a[m]) return Bsearch(x,m+1,right);		else return m;	}	else return -1;}int main(){	int m=Bsearch(3,0,4);	if(m==-1)cout<<"搜索失败"<
      
     

　　下面再来一个迭代的：

#include 
     
      using namespace std;int main(){	int a[5]={1,2,3,4,5};//已排好序了	int left =0;	int right =4;	int x=6;	while(left<=right)	{		int m=(left+right)/2;		if(x
      
       a[m]) left =m+1;		else {cout<<"搜索成功"<