C++构造、析构、继承、多态--一道笔试题都考到了

#include <stdio.h>

class A
{
    A()
    {
        printf("A constrution.\n");
     }
    ~A()
    {
        printf("A deconstrution.\n");
    }
    void funA();
   virtual  void funB();
};

 void A::funA()
｛
        printf("A::funA ...\n");
 }    

void A::funB()
｛
        printf("A::funB ...\n");
}

class B : public A
{
public:
    B()
    {
        printf("B constrution.\n");
     }
    ~B()
    {
        printf("B deconstrution.\n");
    }
    void funA();
     virtual  void funB();
};

 void B::funA()
｛
        printf("B::funA ...\n");
 }    

void B::funB()
｛
        printf("B::funB ...\n");
}

void main()
{
    A *a = new B();
    B b;
    a-
();
    a->funB();
    b.funA();
    b.funB();
    delete a;
}

写出输出结果：（呵呵，顺便复习一下g++的编译的几个步骤）