c++拷贝构造函数

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();
}