circlerun.java

nanjing university cs 的java课件。 对新手很有用。付课件中源码。

import java.io.*;

public class CircleRun{
	public static void main(String args[])
	{
		Circle aa = new Circle();
		aa.readInput();
		aa.jisuan();
		aa.display();
	}
}

class Circle{
	private double r;
	private double mian;
	private double zhou;
	
	public void readInput()
	{
		KeyBoardReader input = new KeyBoardReader();
		System.out.println("Enter radius");
		r=input.readDouble();
	}
	public void jisuan()
	{
		mian= Math.PI * r*r;
		zhou = Math.PI * r*2;
	}
	public void display()
	{
		System.out.println("你输入的半径为： "+r);
		System.out.println("圆的面积为： "+mian);
		System.out.println("圆的周长为："+zhou);
	}
}

class KeyBoardReader{
	
	private BufferedReader br;
	
	public KeyBoardReader(){
		br = new BufferedReader(new InputStreamReader(System.in));
	}
	
	public BufferedReader getReader(){
		return this.br;
	}
	
	public void setReader(BufferedReader br){
		this.br = br;
	}
	
	public double readDouble(){
		double value = 0.0;
		try{
			String s = br.readLine();
		//	System.out.println("s: " + s);
			value = Double.parseDouble(s);
		}
		catch(Exception e){
			System.out.println("Exception: " + e.getMessage());
		}
		return value;
	}
	
	public static void main(String[] args){
		KeyBoardReader input = new KeyBoardReader();
		System.out.println("please input double: ");
		double radio = input.readDouble();
		System.out.println("radio: " + radio);
	}
	
}