C++对象的复制/拷贝函数

Maqi 对象


class Maqi {

public:
    string name;
    int age;

    Maqi(string name, int age) : name(name), age(age) {}

    string &getName() {
        return this->name;
    }

    Maqi() {
        cout << " Maqi()" << endl;
    }

    virtual ~Maqi() {
        cout << " ~Maqi()" << endl;
    }

    Maqi(Maqi &maqi) {
        name = maqi.name;
        age = maqi.age;
    }
};

调用

    string *maqi = new string("maqi");
    Maqi *maqis = new Maqi(*maqi, 18);
    cout << "maqis->getName() = " << maqis->getName() << endl;
    cout << "&maqis = " << &maqis << endl;
    Maqi copyMaqi(*maqis);
    cout << "copyMaqi.getName() = " << copyMaqi.getName() << endl;
    cout << "copyMaqi = " << &copyMaqi << endl;
    cout << "==============================================" << endl;
    Maqi changeMqi(copyMaqi);
    cout << "changeMqi.change() = " << changeMqi.getName() << endl;
    cout << "changeMqi = " << &changeMqi << endl;
    cout << "==============================================" << endl;
    string *change = new string("change");
    Maqi third = changeMqi;
    third.name = *change;
    cout << "third.change() = " << third.getName() << endl;
    cout << "third = " << &third << endl;
    cout << "changeMqi.change() = " << changeMqi.getName() << endl;
    cout << "==============================================" << endl;
    delete maqis;

总结:
1.对象的拷贝函数和复制 都是生成新的对象。
2.拷贝函数等同于 Maqi third = changeMqi; 即:

Maqi copyMaqi(*maqis);
等同于 
Maqi third = changeMqi

3.但是如果重写 Maqi(Maqi &maqi)拷贝函数,其成员赋值将受其影响,比如删除 name = maqi.name;,将输出如下结果:也就是拷贝和复制都会走拷贝函数。

maqis->getName() = maqi
&maqis = 0x28fd98
copyMaqi.getName() =
copyMaqi = 0x28fd78
==============================================
changeMqi.change() =
changeMqi = 0x28fd58
==============================================
third.change() = change
third = 0x28fd38
changeMqi.change() =
==============================================

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转载自blog.csdn.net/qq_20330595/article/details/82219103
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