1.拷贝构造函数

拷贝构造函数的调用时机

class A
{
public://默认构造函数A(){m_Hp = 100;cout << "A默认构造函数调用完毕" << endl;}//有参构造函数A(int hp){m_Hp = hp;cout << "A有参构造函数调用完毕" << endl;}A(const A& a){m_Hp = a.m_Hp;cout << "A拷贝构造函数调用完毕" << endl;}~A(){cout << "A析构函数调用完毕" << endl;}private:int m_Hp;
};

1.用已经创建过的对象来初始化对象

void func1()
{cout << "---------func1----------" << endl;A a1(10);A a2(a1);
}

2.函数的传参
A a = a1;等效于A a(a1);

void test(A a)
{}void func2()
{cout << "---------func2----------" << endl;A a1;test(a1);
}

3.函数的返回值

A test3()
{A a(40);return a;
}
void func3()
{cout << "---------func3----------" << endl;A a = test3();
}

2.初始化列表

class Hero
{
public:Hero(string name,int hp):m_Name(name),m_Hp(hp){}void Print(){cout << "英雄：" << m_Name << "的血量是" << m_Hp << endl;}private:string m_Name;int m_Hp;
};int main()
{Hero h("李白", 100);h.Print();
}