c++官方文档-copy constructor

#include <iostream>

using namespace std;

class Example5

{

        string* ptr;

    public:

        Example5(const string& str):ptr(new string(str)){}

        ~Example5(){delete ptr;}

        //copy constructor

        Example5(const Example5& x):ptr(new string(x.content())){

            cout<<"copy constructor"<<endl;

        }

        //access content;

        const string& content()const{return *ptr;}

};

int main()

{

    Example5 foo("Example");

    Example5 bar = foo;

    cout<<"bar's content:"<<bar.content()<<'\n';

    return ;

}