C++临时对象与右值引用

右值引用：必须保存在变量中，没有地址的量：右值 

#include <iostream>

using namespace std;
class A
{
public:
    A()
    {
        cout<<"这是A的构造函数"<<endl;
    }
    virtual void showInfo()
    {
        cout<<"aaaaaaaaaaaaaaaaaa"<<endl;
    }

    virtual~A()
    {
        cout<<"这是A的析构函数"<<endl;
    }
};


class B:public A
{
public:
    B()
    {
        cout<<"这是B的构造函数"<<endl;
    }
    void showInfo()
    {
        cout<<"bbbbbbbbbbbbbbbb"<<endl;
    }
    ~B()
    {
        cout<<"这是B的析构函数"<<endl;
    }
};

int main(int argc, char *argv[])
{
    A *a1=new B;
    a1->showInfo();
    delete a1;
cout<<"*************************"<<endl;
    A a2=B();
    a2.showInfo();

cout<<"****************"<<endl;
A &&a3=B();
a3.showInfo();


    return 0;
}

C++右值引用std：：move

#include <iostream>

using namespace std;
class A
{
public:
    A()
    {
        cout<<"这是A的构造函数"<<endl;
    }
    virtual void showInfo()
    {
        cout<<"aaaaaaaaaaaaaaaaaa"<<endl;
    }

    virtual~A()
    {
        cout<<"这是A的析构函数"<<endl;
    }
};


class B:public A
{
public:
    B()
    {
        cout<<"这是B的构造函数"<<endl;
    }
    void showInfo()
    {
        cout<<"bbbbbbbbbbbbbbbb"<<endl;
    }
    ~B()
    {
        cout<<"这是B的析构函数"<<endl;
    }
};

int main(int argc, char *argv[])
{
    A *a1=new B;
    a1->showInfo();
    delete a1;
cout<<"*************************"<<endl;
    A a2=B();
    a2.showInfo();

cout<<"****************"<<endl;
A &&a3=B();
a3.showInfo();

 A &&a4=std::move(a2);
 a4.showInfo();


    return 0;
}