C++ 走向远洋——44（项目一、点—圆—圆柱类族的设计、派生类）
*/
* 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8日
* 版本号：V1.0
* 问题描述：类的派生
* 程序输入：无
* 程序输出：见运行结果
*/
#include <iostream> // 点类的实现
using namespace std;
class Point
{
public:
Point(double x=0,double y=0); //构造函数
void setPoint(double,double); //设置坐标值
double getX( ) const {return x;} //读x坐标
double getY( ) const {return y;} //读y坐标
void show();
protected: //受保护成员
double x,y;
};
//Point的构造函数
Point::Point(double a,double b)
{
x=a;
y=b;
}
//设置x和y的坐标值
void Point::setPoint(double a,double b)
{
x=a;
y=b;
}
void Point::show()
{
cout<<"（"<<x<<","<<y<<"）"<<endl;
}
int main( )
{
Point p(2.4,5.1);
p.show();
p.setPoint(1.8,3.2);
p.show();
return 0;
}
运行结果：
#include <iostream> //圆类的实现
using namespace std;
class Point
{
public:
Point(double x=0,double y=0); //构造函数
void setPoint(double,double); //设置坐标值
double getX( ) const
{
return x; //读x坐标
}
double getY( ) const
{
return y; //读y坐标
}
void show();
protected: //受保护成员
double x,y;
};
//Point的构造函数
Point::Point(double a,double b)
{
x=a;
y=b;
}
//设置x和y的坐标值
void Point::setPoint(double a,double b)
{
x=a;
y=b;
}
void Point::show()
{
cout<<"["<<x<<","<<y<<"]"<<endl;
}
class Circle:public Point //circle是Point类的公用派生类
{
public:
Circle(double x=0,double y=0,double r=0); //构造函数
void setRadius(double); //设置半径值
double getRadius( ) const; //读取半径值
double area ( ) const; //计算圆面积
void show();
protected:
double radius;
};
//定义构造函数，对圆心坐标和半径初始化
Circle::Circle(double a,double b,double r):Point(a,b),radius(r) { }
//设置半径值
void Circle::setRadius(double r)
{
radius=r;
}
//读取半径值
double Circle::getRadius( ) const
{
return radius;
}
//计算圆面积
double Circle::area( ) const
{
return 3.14159*radius*radius;
}
//输出圆的信息
void Circle::show()
{
cout<<"Center=（"<<x<<", "<<y<<"）, r="<<radius<<", area="<<area( )<<endl;
}
int main( )
{
Circle c(3.1,5,6.7);
cout<<"original circle:\n";
c.show();
c.setPoint(3,3);
cout<<"new circle:\n";
c.show();
return 0;
}运行结果：
#include <iostream> //圆柱类的实现
using namespace std;
class Point
{
public:
Point(double x=0,double y=0); //构造函数
void setPoint(double,double); //设置坐标值
double getX( ) const
{
return x; //读x坐标
}
double getY( ) const
{
return y; //读y坐标
}
void show();
protected: //受保护成员
double x,y;
};
//Point的构造函数
Point::Point(double a,double b)
{
x=a;
y=b;
}
//设置x和y的坐标值
void Point::setPoint(double a,double b)
{
x=a;
y=b;
}
void Point::show()
{
cout<<"["<<x<<","<<y<<"]"<<endl;
}
class Circle:public Point //circle是Point类的公用派生类
{
public:
Circle(double x=0,double y=0,double r=0); //构造函数
void setRadius(double); //设置半径值
double getRadius( ) const; //读取半径值
double area ( ) const; //计算圆面积
void show();
protected:
double radius;
};
//定义构造函数，对圆心坐标和半径初始化
Circle::Circle(double a,double b,double r):Point(a,b),radius(r) { }
//设置半径值
void Circle::setRadius(double r)
{
radius=r;
}
//读取半径值
double Circle::getRadius( ) const
{
return radius;
}
//计算圆面积
double Circle::area( ) const
{
return 3.14159*radius*radius;
}
//输出圆的信息
void Circle::show()
{
cout<<"Center=["<<x<<", "<<y<<"], r="<<radius<<", area="<<area( )<<endl;
}
class Cylinder:public Circle
{
public:
Cylinder (double x=0,double y=0,double r=0,double h=0);//构造函数
void setHeight(double); //设置圆柱高
double getHeight( ) const; //读取圆柱高
double area( ) const; //计算圆柱表面积
double volume( ) const; //计算圆柱体积
void show();
protected:
double height; //圆柱高
};
//定义构造函数
Cylinder::Cylinder(double a,double b,double r,double h) :Circle(a,b,r),height(h){}
//设置圆柱高
void Cylinder::setHeight(double h)
{
height=h;
}
//读取圆柱高
double Cylinder::getHeight( ) const
{
return height;
}
//计算圆柱表面积
double Cylinder::area( ) const
{
return 2*Circle::area( )+2*3.14159*radius*height;
}
//计算圆柱体积
double Cylinder::volume() const
{
return Circle::area()*height;
}
void Cylinder::show()
{
cout<<"Center=["<<x<<","<<y<<"], r="<<radius<<", h="<<height
<<"\narea="<<area( )<<", volume="<<volume( )<<endl;
}
int main( )
{
Cylinder cy1(3.5,6.4,5.2,10);
cout<<"\noriginal cylinder:\nx=";
cy1.show();
cy1.setHeight(15);
cy1.setRadius(7.5);
cy1.setPoint(5,5);
cout<<"\nnew cylinder:\n";
cy1.show();
return 0;
}运行结果：
