虚函数_构造函数_测试_VS2010x86

#include <stdio.h>
#include <windows.h>

class A
{
public:
    A()
    {
        printf("A constructor\n");
    }

public:
    virtual void SayHi()
    {
        printf("A say hi\n");
    }
};

class B :public A
{
public:
    B()
    {
        printf("B constructor\n");
    }

    B(int _i)
    {
        printf("B constructor : %d\n", _i);
    }

public:
    void SayHi()
    {
        A::SayHi();
        printf("B say hi\n");
    }
};

class C :public B
{
public:
    void SayHi()
    {
        // 要调用父类的SayHi()，就需要指明是哪个父类的SayHi()。它不会默认去调用父类的SayHi()
        B::SayHi();
        printf("C say hi\n");
    }
};

void main()
{
    // 子类创建时，必然会调用父类的构造函数
    B *pb = new B();
    B *pb1= new B(2);

    printf("\n");

    C c;
    c.SayHi();

    system("pause");
}

A constructor
B constructor
A constructor
B constructor : 2

A constructor
B constructor
A say hi
B say hi
C say hi
请按任意键继续. . .