例子:
1
#include<iostream>
using namespace std;
class A
{
public:
A(){};
virtual void display()
{cout<<"This is A"<<endl;}};
class B:public A
{
public:
B(){};
void display()
{cout<<"This is B"<<endl;}};
int main(void)
{
A* a1=new B();
a1->display();
}
2.
#include<iostream>
using namespace std;
class A
{
public:
A(){};
void display()
{cout<<"This is A"<<endl;}};
class B:public A
{
public:
B(){};
void display()
{cout<<"This is B"<<endl;}};
int main(void)
{
A* a1=new B();
a1->display();
}
结果:
1.This is B
2.This is A