circle.java

包括角谷,色子,回文等矿大JAVA实验课留的作文

import java.io.IOException;
class circle1{
	double radius;
 public void circle1(double x)
	{    
		radius=x;
	}
}
public class circle {
	public static String readString()
	{
		int ch;
		String r="";
		boolean done=false;
		while(!done)
		try{
			ch=System.in.read();
			if(ch<0||ch==0xd)
				done=true;
			else
				r=r+(char)ch;
		
		}catch(IOException e)
		{ System.out.println("error");done=true; };
		
		return r;
	}
	
	public static void main(String[]args)
	{
		String str;
		System.out.println("请输入一个半径值！ ");	
		str=readString();
		circle1	r1=new circle1();
		if(Double.parseDouble(str)<0)
		System.out.println("输入错误");
		else 
		{
			r1.circle1(Double.parseDouble(str));
		    System.out.println("周长为"+Math.PI*2*r1.radius+"  面积为"+Math.PI*r1.radius*r1.radius);
	     }
	}
	
	
	
}