抽象类练习（c++ primer plus）

   

 

今晚看《c++ primer plus》做的练习题，呵呵，做的不怎么好，希望高手如果有时间指点一二，谢谢诶！  《c++ primer plus》p475练习题3；修改 basedma—lacksdma—hasdma类，让他们都从一个基类派生出来，实现和程序单13.10一样的基本功能，注意使用基类数组指针，在类中添加view（）方法显示数据

代码如下：在vs2005中编译通过！

//filename:dma_abc.h

//定义类，声明类的方法

////#pragma once#ifndef DMA_ABC_H_#define DMA_ABC_H_#include<iostream>namespace kp{ //////////////////////////virtual base class dma//////////////////////// class Dma{ private:char *label;int rating; protected:const char *returnlabel()const{return label;}int returnrating()const{return rating;} public:Dma(const char *l="null",int r=0);Dma(const Dma &dma);virtual ~Dma();Dma &operator=(const Dma &dma);virtual void View()const =0 ;friend std::ostream &operator<<(std::ostream &os,const Dma &dma); }; ////////////////////////////class basedma :public dma/////////////////////////// class BaseDma:public Dma{ public:BaseDma(const char *l="null",int r=0):Dma(l,r){}BaseDma(const BaseDma &bd):Dma(bd){}//BaseDma&operator=(const BaseDma &bd);virtual void View()const ;friend std::ostream &operator<<(std::ostream &os,const BaseDma &bd); }; ////////////////////////////class lacksdma:public dma//////////////////////////// class LacksDma:public Dma{ private:enum{COL_LEN=40};char color[COL_LEN]; public:LacksDma(const char *c="black",const char *l="null",int r=0);LacksDma(const char *c,const Dma &Dma);virtual void View()const ;friend std::ostream &operator<<(std::ostream &os,const LacksDma &ld); }; ////////////////////////class hasdma:public dma///////////////////////// class HasDma:public Dma{ private:char *style; public:HasDma(const char *s="none",char *l="null",int r=0);HasDma(const char *s,const Dma &dma);HasDma(const HasDma &hd);virtual ~HasDma(); virtual void View()const;HasDma &operator=(const HasDma &hd);friend std::ostream&operator<<(std::ostream &os,const HasDma &hd); };}#endif

 

//filename:dma_abc.cpp

//类方法的实现（定义）

#include<iostream>#include<cstring>#include"dma_abc.h"namespace kp{ ////////////////////virtual base class dma methods///////////////// Dma::Dma(const char *l,int r) {label=new char[std::strlen(l)+1];std::strcpy(label,l);rating=r; } Dma::Dma(const Dma &dma) {label=new char[std::strlen(dma.label)+1];std::strcpy(label,dma.label);rating=dma.rating; } Dma::~Dma() {delete []label; } Dma &Dma::operator=(const Dma &dma) {if (this==&dma) return *this;delete []label;label=new char[std::strlen(dma.label)+1];std::strcpy(label,dma.label);rating=dma.rating;return *this; } std::ostream &operator<<(std::ostream &os,const Dma &dma) {os<<"label: "<<dma.label<<std::endl;os<<"rate: "<<dma.rating<<std::endl;return os; } /////////////////////////class basedma:public dma methods//////////////// void BaseDma::View()const {std::cout<<"label: "<<returnlabel()<<std::endl;std::cout<<"rate: "<<returnrating()<<std::endl; } std::ostream &operator<<(std::ostream &os,const BaseDma &bd) {os<<(const Dma&)bd;return os; } ////////////////////////////////class lacksdma:public dma methods////////////////// LacksDma::LacksDma(const char *c,const char *l,int r):Dma(l,r) {std::strncpy(color,c,COL_LEN-1);color[COL_LEN-1]='/0'; } LacksDma::LacksDma(const char *c,const Dma &dma):Dma(dma) {std::strncpy(color,c,COL_LEN-1);color[COL_LEN-1]='/0'; } void LacksDma::View()const {std::cout<<"label: "<<returnlabel()<<std::endl;std::cout<<"rate: "<<returnrating()<<std::endl;std::cout<<"color: "<<color<<std::endl;; } std::ostream&operator<<(std::ostream &os,const LacksDma &ld) {os<<(const Dma&)ld;os<<"color: "<<ld.color;return os; } ////////////////////////////////////class hasdma:public dma methods/////////// HasDma::HasDma(const char *s,char *l,int r):Dma(l,r) {style=new char[std::strlen(s)+1];std::strcpy(style,s); } HasDma::HasDma(const char *s,const Dma&dma):Dma(dma) {style=new char[std::strlen(s)+1];std::strcpy(style,s); } HasDma::~HasDma() {delete []style; } HasDma::HasDma(const HasDma &hd):Dma(hd) {style=new char[std::strlen(hd.style)+1];std::strcpy(style,hd.style); } void HasDma::View()const {std::cout<<"label: "<<returnlabel()<<std::endl;std::cout<<"rate: "<<returnrating()<<std::endl;std::cout<<"style: "<<style<<std::endl; } HasDma & HasDma::operator =(const HasDma &hd) {if (this==&hd) return *this;Dma::operator =(hd);style=new char[std::strlen(hd.style)+1];std::strcpy(style,hd.style);return *this; } std::ostream&operator<<(std::ostream &os,const HasDma &hd) {os<<(const Dma&)hd;os<<"style: "<<hd.style<<std::endl;return os; }}

//finename:dma_abcmain.cpp
//主函数，用来测试类

////#include<iostream>#include"dma_abc.h"int main(int argv,char **argc){ using std::cout; using std::endl; using kp::Dma; using kp::HasDma; using kp::LacksDma; using kp::BaseDma; Dma *p[6]; p[0]=new BaseDma("portablely",8); p[1]=new LacksDma ("red","blimpo",4); p[2]=new HasDma("mercator","buffalo",5); /*cout<<*p[0]<<endl; cout<<*p[1]<<endl; cout<<*p[2]<<endl;*/ p[4]=p[1]; p[3]=new BaseDma(); p[5] =p[3]; /* cout<<*p[3]<<endl; cout<<*p[4]<<endl; cout<<*p[5];*/ for (int i=0;i<6;i++)p[i]->View(); for (int i=0;i<4;i++)delete p[i]; return 0;}

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