！壞人必需做好事！

#include <vector>
#include <iostream>

    using namespace std;
    class A
    {
    public:
        A(){cout << "A is Construct" << endl;}
        ~A(){cout << "A is Destruct" << endl;}
    };

    class B
    {
    public:
        B(){cout << "B is Construct" << endl;}
        ~B(){cout << "B is Destruct" << endl;}
    };

    class C : public A
    {
    public:
        C(){cout << "C is Construct" << endl;}
        ~C(){cout << "C is Destruct" << endl;}

        B member;
    };

    int main()
    {
        C* c = new C;
        delete c;
        return 0;
    }

輸出：
A is Construct
B is Construct
C is Construct
C is Destruct
B is Destruct
A is Destruct

    int main()
    {
        A* c = new C;
        delete c;
        return 0;
    }

輸出：
A is Construct
B is Construct
C is Construct
A is Destruct

這說明了轉型的危險性。