Java中Math类常用方法代码详解

public class Demo{
  public static void main(String args[]){ 
    /** 
     *Math.sqrt()//计算平方根
     *Math.cbrt()//计算立方根
     *Math.pow(a, b)//计算a的b次方
     *Math.max( , );//计算最大值
     *Math.min( , );//计算最小值
     */ 
    System.out.println(Math.sqrt(16));  //4.0 
    System.out.println(Math.cbrt(8));  //2.0
    System.out.println(Math.pow(3,2));   //9.0
    System.out.println(Math.max(2.3,4.5));//4.5
    System.out.println(Math.min(2.3,4.5));//2.3
    /** 
     * abs求绝对值 
     */ 
    System.out.println(Math.abs(-10.4));  //10.4 
    System.out.println(Math.abs(10.1));   //10.1 
    /** 
     * ceil天花板的意思，就是返回大的值
     */ 
    System.out.println(Math.ceil(-10.1));  //-10.0 
    System.out.println(Math.ceil(10.7));  //11.0 
    System.out.println(Math.ceil(-0.7));  //-0.0 
    System.out.println(Math.ceil(0.0));   //0.0 
    System.out.println(Math.ceil(-0.0));  //-0.0 
    System.out.println(Math.ceil(-1.7));  //-1.0
    /** 
     * floor地板的意思，就是返回小的值 
     */ 
    System.out.println(Math.floor(-10.1)); //-11.0 
    System.out.println(Math.floor(10.7));  //10.0 
    System.out.println(Math.floor(-0.7));  //-1.0 
    System.out.println(Math.floor(0.0));  //0.0 
    System.out.println(Math.floor(-0.0));  //-0.0 
    /** 
     * random 取得一个大于或者等于0.0小于不等于1.0的随机数 
     */ 
    System.out.println(Math.random()); //小于1大于0的double类型的数
    System.out.println(Math.random()*2);//大于0小于1的double类型的数
    System.out.println(Math.random()*2+1);//大于1小于2的double类型的数
    /** 
     * rint 四舍五入，返回double值 
     * 注意.5的时候会取偶数  异常的尴尬=。=
     */ 
    System.out.println(Math.rint(10.1));  //10.0 
    System.out.println(Math.rint(10.7));  //11.0 
    System.out.println(Math.rint(11.5));  //12.0 
    System.out.println(Math.rint(10.5));  //10.0 
    System.out.println(Math.rint(10.51));  //11.0 
    System.out.println(Math.rint(-10.5));  //-10.0 
    System.out.println(Math.rint(-11.5));  //-12.0 
    System.out.println(Math.rint(-10.51)); //-11.0 
    System.out.println(Math.rint(-10.6));  //-11.0 
    System.out.println(Math.rint(-10.2));  //-10.0 
    /** 
     * round 四舍五入，float时返回int值，double时返回long值 
     */ 
    System.out.println(Math.round(10.1));  //10 
    System.out.println(Math.round(10.7));  //11 
    System.out.println(Math.round(10.5));  //11 
    System.out.println(Math.round(10.51)); //11 
    System.out.println(Math.round(-10.5)); //-10 
    System.out.println(Math.round(-10.51)); //-11 
    System.out.println(Math.round(-10.6)); //-11 
    System.out.println(Math.round(-10.2)); //-10 
  } 
}