取整函数

import static java.lang.Math.*;

public class test {
    public static void main(String[] args) {
        // 向上取整
        System.out.println(ceil(-1.5)); // -1.0
        System.out.println(ceil(1.5)); // 2.0
        System.out.println(ceil(-1.3)); // -1.0
        System.out.println(ceil(1.3)); // 2.0
        System.out.println(ceil(-1.7)); // -1.0
        System.out.println(ceil(1.7)); // 2.0
        System.out.println("--------------------");
        // 向下取整
        System.out.println(floor(-1.5)); // -2.0
        System.out.println(floor(1.5)); // 1.0
        System.out.println(floor(-1.3)); // -2.0
        System.out.println(floor(1.3)); // 1.0
        System.out.println(floor(-1.7)); // -2.0
        System.out.println(floor(1.7)); // 1.0
        System.out.println("--------------------");
        // 四舍五入取整
        System.out.println(round(-1.5)); // -1
        System.out.println(round(1.5)); // 2
        System.out.println(round(-1.3)); // -1
        System.out.println(round(1.3)); // 1
        System.out.println(round(-1.7)); // -2
        System.out.println(round(1.7)); // 2
    }
}