package day01; public class Case12 {
      public static void main(String[] args) {
          System.out.println(Math.abs(-3.14));//绝对值         System.out.println(Math.ceil(3.9));//向上取整         System.out.println(Math.floor(3.1));//向下取整         System.out.println(Math.round(20.4));//四舍五入         System.out.println(Math.PI);     } }