c++和java類的簡單實現

定義一個圓類，實現面積，周長的計算，定義一個圓柱類，通過繼承圓類，實現圓柱的底面積，底面周長，並求出圓柱體的體積

初學寫的不好，有問題希望大家指導，像大家學習。

c++的實現：（複習類）

#include <iostream>
#include <cmath>
#define PI 3.14159       // 宏定義π=3.14159
using namespace std;

class Circle
{
protected:
	double R;
	double circlearea,area; // 底圓周長和麪積
public:
	Circle(double);
	void Input();
	void Circlearea();
	void Area();
	void Output();
};

Circle::Circle(double r)
{
	R=r;
}

void Circle::Input()
{
	cout<<"圓的半徑: "<<endl;
	cin>>R;
}

void Circle::Circlearea()
{
	circlearea=2*PI*R;
}

void Circle::Area()
{
	area=PI*R*R;
}

void Circle::Output()
{
	cout<<"圓的周長："<<circlearea<<endl;
	cout<<"圓的面積："<<area<<endl;
}

class Cylinder:public Circle
{
public:
    Cylinder(double ,double );
	void Input();
	void Bulk();
	void Output();
protected:
	double height,bulk; // 體積
};

Cylinder::Cylinder(double r,double h):Circle(r),height(h){}

void Cylinder::Input()
{
	Circle::Input();
	cout<<"以此圓爲底的圓柱的高: ";
	cin>>height;
}

void Cylinder::Bulk()
{
	bulk=PI*R*R*height;
}

void Cylinder::Output()
{
	cout<<"圓柱:"<<endl;
	Circle::Output();
	cout<<"圓柱體的體積："<<bulk<<endl;
}

int main()
{
	Circle x(2);
	x.Circlearea();
	x.Area();
	x.Output();
	Cylinder b(1,1);
	b.Circlearea();
	b.Area();
	b.Bulk();
	b.Output();
	return 0;
}

java的實現：（未修改版）

package Text1;

public class Circle{
		 
    protected double radius;
    
    public Circle(){//圓類
		radius=0;
	}
		
	public Circle(double radius) {
		this.radius = radius;
	}
	
	public double getRadius() {
		return radius;
	}
	public void setRadius(double radius) {
		this.radius = radius;
	}
	public double area(){
		return 3.14*radius*radius;
	}
		
    }
class Cyliinder extends Circle{//圓柱類繼承圓類
		
    protected double height;
    
	public Cyliinder(){
		height=0;
	}
		
	public Cyliinder(double radius,double height) {
	    super(radius);
	    this.height = height;
	}
	public double getHeight() {
	    return height;
	}
	public void setHeight(double height) {
		this.height = height;
	}
		
	public double volume(){
		return area()*height;
	}
		
	}

public class aa{
	public static void main(String[] args) {
		
	Circle c1=new Circle(1);
	System.out.println("圓:");
	//輸出圓的半徑
	System.out.println(c1.getRadius());
	//輸出圓的面積
	System.out.println(c1.area());	
	
	Cyliinder c2=new Cyliinder(3,5);
	System.out.println("圓柱:");
	
	System.out.println(c2.getRadius());
		//輸出高
	System.out.println(c2.getHeight());
	   //輸出面積
	System.out.println(c2.area());
		//輸出體積
	System.out.println(c2.volume());
		}
}

java代碼（刪改之後）:

package cn.demo;

/**
* @ClassName: Circle 
* @Description: 圓的類 
* @author myname
* @date 2016-6-20 下午9:24:23 
* @version 1.0
 */

public class Circle
{
	/**半徑*/ 
    protected double radius;
    
    public Circle()
    {
		radius=0;
	}
		
	public Circle(double radius) 
	{
		this.radius = radius;
	}
	
	public double getRadius() 
	{
		return radius;
	}
	
	public void setRadius(double radius)
	{
		this.radius = radius;
	}
	
	public double area()
	{
		return 3.14*radius*radius;
	}
		
}

package cn.demo;

/**
* @ClassName: Cyliinder 
* @Description: 圓柱類
* @author myname
* @date 2016-6-20 下午9:25:37 
* @version 1.0
 */

public class Cyliinder extends Circle
{
	/**高*/
    private double height;
    
	public Cyliinder()
	{
		height=0;
	}
		
	public Cyliinder(double radius,double height)
	{
	    super(radius);
	    this.height = height;
	}
	
	public double getHeight() 
	{
	    return height;
	}
	
	public void setHeight(double height) 
	{
		this.height = height;
	}
		
	public double volume()
	{
		return area()*height;
	}
		
}

package cn.test;

import cn.demo.Circle;
import cn.demo.Cyliinder;


public class DemoTest 
{
	/**
	 * @param <Circle> 
	 *
	 * @Title: main 
	 * @Description: test
	 * @param @param args    設定文件 
	 * @return void    返回類型 
	 * @throws 
	 */
	
	public static void main(String[] args) 
	{
		Circle c1=new Circle(1);
		System.out.println("圓:");
		//輸出圓的半徑
		System.out.println(c1.getRadius());
		//輸出圓的面積
		System.out.println(c1.area());	
		
		Cyliinder c2=new Cyliinder(3,5);
		System.out.println("圓柱:");
		
		System.out.println(c2.getRadius());
			//輸出高
		System.out.println(c2.getHeight());
		   //輸出面積
		System.out.println(c2.area());
			//輸出體積
		System.out.println(c2.volume());
	}

}