Java中Math类的常用方法

public class MathDemo {
public static void main(String args[]){
/**
* 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，注意一些特殊值
*/
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

/**
* 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

/**
* max 两个中返回大的值,min和它相反，就不举例了
*/
System.out.println(Math.max(-10.1, -10));
//-10.0
System.out.println(Math.max(10.7, 10));
//10.7
System.out.println(Math.max(0.0, -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());
//0.08417657924317234
System.out.println(Math.random());
//0.43527904004403717

/**
* rint 四舍五入，返回double值
* 注意.5的时候会取偶数
*/
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
}

}