二分搜索代码（c++)

#include<iostream>

using namespace std;

template<typename Type>

int BinarySearch(Type a[],const Type& x,int n) //&x是引用型

{

int left=0,right=n-1;

int num=0; //测试

while(left<=right)

{

int middle=(left+right)/2;

cout<<"第"<<++num<<"次："<<middle<<endl; //测试

if(x==a[middle])return middle;

if(x>a[middle])left=middle+1;

else right=middle-1;

}

return -1;

}

int main()

{

int a[10]={0,1,2,3,4,5,6,7,8,9},result;

int x;

do{

cout<<"（输入-1结束）请输入要二分搜索的数：";

cin>>x;

result=BinarySearch(a,x,10);

if(result!=-1)

{

cout<<"存在数："<<x<<endl;

}

else

{

cout<<"不存在数："<<x<<endl;

}

}while(x!=-1);

return 0;

}