c++虚析构函数

#include <iostream>
using namespace std;
class Base
{
private:
    int* a;
public:
    Base(){
        cout<<"base construct new int"<<endl;
        a = new int();
    }
    //必须申明为虚析构函数，不然子类的析构函数将不会被执行
    virtual ~Base(){
        cout<<"base destruct del int"<<endl;
        delete a;
    }
};
class Child : public Base{
private:
    int* b;
public:
    Child(){
        cout<<"Child construct new int"<<endl;
        b = new int();
    }
    ~Child(){
        cout<<"Child destruct del int"<<endl;
        delete b;
    }
};
int main()
{
    Base* b;
    b = new Child();
    delete b;
}