package javase9;

import java.text.DecimalFormat;

public class javase9_2 {
     static public void SimpleFormat(String pattern, double value){

        DecimalFormat myFormat=new DecimalFormat(pattern);  //实例化DecimalFormat对象
        String  put=myFormat.format(value);   //进行数字格式化
        System.out.println("圆的面积："+value+" "+pattern+" "+put);
    }

    public static double GetRoundArea(double r){
        return  Math.PI*Math.pow(r,2);  //求圆的面积

    }
    public static void main(String[] args) {
        System.out.println();
        SimpleFormat("圆的面积保留五位小数："+"#.#####",GetRoundArea(2));
         
    }
}