文章标题

         /** * 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 
    }