【虚】示例代码

三.虚析构

#include <iostream>
using namespace std;

class Base{
public:
    virtual ~Base(){ cout<<"Base destructor\n"; }
};

class Derived:public Base{
public:
    Derived(){ iPtr = new int(0); }
    ~Derived(){
        cout <<"Derived destructor\n";
        delete iPtr; //  这里会调用 基类 析构函数?！！！
    }

private:
    int *iPtr;
};

void fun(Base *b){ delete b; }//delete会调用析构函数，这里调用派生类的析构

void main(){
    Base *b=new Derived(); //基类型指针d 指向派生类对象，分配了内存，就要在对象消失时 释放相应的内存
                          //通过 基类指针b 删除 派生类对象
    fun(b);
}