[原]C++程序示例：涉及到抽象类、继承…

C++复习题。

有助于理解：

1. .h与.cpp分离
2. 基类、派生类、抽象类
3. 多态、纯虚函数
4. 对象指针、引用
5. 派生类使用基类的构造函数
6. 。。。

==================================================================================================

t3.h

#ifndef T3_H_INCLUDED

#define T3_H_INCLUDED

//此程序定义一个Shape类。矩形，圆形从Shape继承。矩形可以计算面积，改变大小，比较大小。改变大小，比较大小。

//继承、虚函数、重载

//protected成员可以被派生类直接访问，private成员不可以被派生类访问

//涉及析构

class Shape{

protected:

float length;

float width;

float radius;

public:

Shape();

Shape(float r);

Shape(float l,float w);

~Shape();

float getRadius();

float getWidth();

float getLength();

virtual void display()=0;

virtual void changeSize(float l,float w)=0;

virtual double getArea()=0;

virtual bool compareSize(Shape* s0)=0; 

};

class Rectangular:public Shape{

public:

Rectangular():Shape(){}

Rectangular(float l,float w):Shape(l,w){}

void display();

void changeSize(float l,float w);

double getArea();

bool compareSize(Shape* s0); 

};

class Circle:public Shape{

public:

Circle():Shape(){}

Circle(float r):Shape(r){}

void display();

void changeSize(float l,float w);

double getArea();

bool compareSize(Shape* s0); 

};

#endif 

==================================================================================================

t3.cpp

#include

#include "t3.h"

using namespace std;

Shape::Shape(){length=0;width=0;radius=0;}

Shape::Shape(float r){radius=r;}

Shape::Shape(float l,float w){length=l;width=w;}

Shape::~Shape(){

cout<<"I was dead."<<endl;

}

float Shape::getRadius(){

return radius;

}

float Shape::getLength(){

return length;

}

float Shape::getWidth(){

return width;

}

//Shape end

void Rectangular::display(){

cout<<"I'm a rectangular."<<endl;

}

void Rectangular::changeSize(float l,float w){

length=length+l;

width=width+w;

}

double Rectangular::getArea(){

return length*width;

}

bool Rectangular::compareSize(Shape* s0){

return this->getArea()>s0->getArea();

}

//Rectangular end

void Circle::display(){

cout<<"I'm a circle."<<endl;

}

void Circle::changeSize(float l,float w=0){

radius=radius+l;

}

double Circle::getArea(){

return 3.14*radius*radius;

}

bool Circle::compareSize(Shape* s0){

return this->getArea()>s0->getArea();

}

//Circle end

int main(){

Rectangular r1=Rectangular();

r1.display();

cout<<"My area
is:"<<r1.getArea()<<endl;

r1.changeSize(5,6);

r1.display();

cout<<"My area
is:"<<r1.getArea()<<endl;

Rectangular r2=Rectangular(3,4);

r2.display();

cout<<"My area
is:"<<r2.getArea()<<endl;

Circle c1=Circle();

c1.display();

cout<<"My area
is:"<<c1.getArea()<<endl;

c1.changeSize(5);

c1.display();

cout<<"My area
is:"<<c1.getArea()<<endl;

Circle c2=Circle(6);

c2.display();

cout<<"My area
is:"<<c2.getArea()<<endl;

Shape *p;

p=&c2;

cout<<r2.compareSize(p)<<endl;;

}

作者：gcy77 发表于2014-3-12 15:16:28 原文链接

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