引用的问题
输出运算符的重载一定要加引用?
可是可以 不过效率很低下 构造了一个临时对象 最后还要析构= =
#include <iostream>//mooc提交用
using namespace std;//mooc提交用
#include <vector>
#include <map>
class A{
public:
A(){cout<<"A()"<<endl;}
A(A&){cout<<"A(&)"<<endl;}
~A(){cout<<"~A"<<endl;}
};
ostream& operator<<(ostream& out,const A*){out<<"A*的<<"<<endl; return out;}
ostream& operator<<(ostream& out,A){out<<"A的<<"<<endl; return out;}
//ostream& operator<<(ostream& out,const A&){out<<"const A&的<<"<<endl; return out;}
int main(int argc, const char * argv[] )
{//---------------main--------------
A a;
cout<<&a;
cout<<a;
cout<<"------"<<endl;
//---------------main--------------
return 0;
}举报