31 lines
651 B
C++
31 lines
651 B
C++
#include <iostream>
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#include<string>
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using namespace std;
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class A {
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public:
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void f(int i){cout<<"A::f()"<<endl;};
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};
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class B: public A {
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public:
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virtual void f(int i){cout<<"B::f()"<<endl;}
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};
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class C: public B {
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public:
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void f(int i){cout<<"C::f()"<<endl;}
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};
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//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
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class D: public C{
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public:
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void f (int){cout<<"D::f()"<<endl;}
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};
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int main(){
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A *pA,a;
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B *pB, b; C c; D d;
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pA=&a; pA->f(1); //调用A::f
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pB=&b; pB->f(1); //调用B::f
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pB=&c; pB->f(1); //调用C::f
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pB=&d; pB->f(1); //调用D::f
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system("pause");
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return 0;
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}
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