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
	}
}