*/ * Copyright (c) 2016,烟台大学计算机与控制工程学院 * All rights reserved. * 文件名:text.cpp * 作者:常轩 * 微信公众号:Worldhello * 完成日期:2016年5月22日 * 版本号:V1.0 * 问题描述:十二周阅读程序 * 程序输入:无 * 程序输出:见运行结果 */ //(1)虚函数 #include<iostream> using namespace std; class A { int a; public: A():a(5){} virtual void print()const { cout<<a;} }; class B: public A { char b; public: B() { b='E'; } void print() const { cout<<b; } }; void show(A &x) { x.print(); } int main() { A d1,*p; B d2; p=&d2; d1.print(); d2.print(); p->print(); show(d1); show(d2); cout<<endl; return 0; }
运行结果:
//(2)虚析构函数 #include <iostream> using namespace std; class BASE { private: char c; public: BASE(char n):c(n) {} virtual ~BASE() { cout<<c; } }; class DERIVED:public BASE { private: char c; public: DERIVED(char n):BASE(n+1),c(n) {} ~DERIVED(){ cout<<c; } }; int main(){ DERIVED d('X'); return 0; }
运行结果:
//(3)纯虚函数 #include <iostream> using namespace std; class Base { public: virtual void Who() =0; }; class FirstDerived:public Base { public: void Who() { cout<<"F"; } }; class SecondDerived:public Base { public: void Who() { cout<<"S"; } }; int main() { FirstDerived first_obj; SecondDerived second_obj; Base &bref=first_obj; bref.Who(); bref=second_obj; bref.Who(); Base *bp; bp=&first_obj; bp->Who(); bp=&second_obj; bp->Who(); return 0; }
运行结果: