java基础 Math

 package cn.mantishell.day08.demo04;

 /**
  * java.util.Math类是数学相关的工具类，里面提供类大量的静态方法，完成与数学运算相关的操作
  *
  * public static double abs(double num);获取绝对值
  * public static double ceil(double num);向上取整
  * public static double floor(double num);向下取整
  * public static long round(double num);四舍五入
  */
 public class Demo03Math {
     public static void main(String[] args) {
         //获取绝对值
         System.out.println(Math.abs(-2.5));//2.5
         //向上取整
         System.out.println(Math.ceil(3.9));//4.0
         System.out.println(Math.ceil(3.1));//4.0
         System.out.println(Math.ceil(3.0));//3.0

         System.out.println(Math.floor(10.9));

         System.out.println(Math.round(2.6));
     }
 }