注意类的虚函数的一个用法

#include <iostream> using namespace std; class A { public: A() { cout<<"A Create!"<<endl; } ~A() { cout<<"delete A!"<<endl; } virtual void fun1() { cout<<"A fun1()"<<endl; } void fun2() { cout<<"A fun2()"<<endl; fun1(); } }; class B : public A { public: B() { cout<<"B Create!"<<endl; } ~B() { cout<<"delete B!"<<endl; } virtual void fun1() { cout<<"B fun1()"<<endl; } }; void main() { B testb; testb.fun2(); }

上述代码输出：

A Create!
Create BBBBBBBBBBB
A fun2
B fun1
delete BBBBBBBB
delete A!
Press any key to continue

 

如果fun1()函数为非虚函数时输出如下：

A Create!
B Create!
A fun2()
A fun1()
delete B!
delete A!
Press any key to continue