c++继承-----继承中的构造和析构顺序问题

c++继承-----继承中的构造和析构顺序问题

• 单继承中的构造顺序问题

  • 先构造父类的再构造子类的，析构顺序相反

• 多继承中构造顺序问题

  • 任何构造顺序问题都和初始化参数列表无关

  • 构造顺序和继承顺序一致

单继承

class A 
{
public:
	A() { cout << "A"; }
	~A() { cout << "A" ; }
protected:
};
class B :public A 
{
public:
	B() { cout << "B"; }
	~B() { cout << "B" ; }
};

int main()
{
    B b;
    return 0;

}

多继承 

#include 
using namespace std;
class A 
{
public:
	A() { cout << "A"; }
	~A() { cout << "A" ; }
protected:
};
class B :public A 
{
public:
	B() { cout << "B"; }
	~B() { cout << "B" ; }
};

class C 
{
public:
	C() { cout << "C"; }
	~C() { cout << "C"; }
};
class D
{
public:
	D() { cout << "D"; }
	~D() {cout << "D";}
};

//构造顺序和继承顺序一致:先继承C,再继承A,最后继承D
class F :public C, public A, public D
{
public:
	//任何构造顺序问题，都和初始化参数列表无关
	F() { cout << "F";}
	~F() { cout << "F";}
};
//CADF FDAC
int main() 
{
	F f;
	return 0;
}