31 lines
640 B
C++
31 lines
640 B
C++
#include <iostream>
|
|
#include<string>
|
|
using namespace std;
|
|
class A {
|
|
public:
|
|
void f(int i){cout<<"…A"<<endl;};
|
|
};
|
|
class B: public A {
|
|
public:
|
|
virtual void f(int i){cout<<"…B"<<endl;}
|
|
};
|
|
class C: public B {
|
|
public:
|
|
void f(int i){cout<<"…C"<<endl;}
|
|
};
|
|
//一旦将某个成员函数声明为虚函数后，它在继承体系中就永远为虚函数了
|
|
class D: public C{
|
|
public:
|
|
void f (int){cout<<"…D"<<endl;}
|
|
};
|
|
int main(){
|
|
A *pA,a;
|
|
B *pB, b; C c; D d;
|
|
pA=&a; pA->f(1); //调用A::f
|
|
pB=&b; pB->f(1); //调用A::f
|
|
pB=&c; pB->f(1); //调用A::f
|
|
pB=&d; pB->f(1); //调用A::f
|
|
system("pause");
|
|
return 0;
|
|
}
|