circlearea.java

来自「主要是对于JAVA的编程的基本语言 希望能够帮得上你。」· Java 代码 · 共 24 行

package io;

import java.io.*;

public class CircleArea {
	public static void main(String[] args) {		
			BufferedReader br=new BufferedReader(new InputStreamReader(System.in));
			System.out.print("请输入圆的半径：");
			try {
				double r=Double.parseDouble(br.readLine());
				double area=0;
				if(r>=0){
					area=Math.PI*Math.pow(r, 2);
					System.out.println("圆的面积为"+area);
				}else{
					System.err.println("输入半径不合法。");
				}				
			} catch (NumberFormatException e) {
				e.printStackTrace();
			} catch (IOException e) {				
				e.printStackTrace();
			}		
	}
}