Math类

public class Demo01 {
    public static void main(String[] args) {
        System.out.println(Math.PI);//3.141592653589793

        System.out.println("===========常用=============");
        System.out.println(Math.round(3.1));//四舍五入 3
        System.out.println(Math.round(3.6));//四舍五入 4
        System.out.println(Math.ceil(3.1));//向上取整 4.0
        System.out.println(Math.floor(3.1));//向下取整 3.0
        System.out.println(Math.random());//随机数 [0，1)  0.0805946037397508

        System.out.println(Math.pow(2, 3));//2的三次幂 8.0
        System.out.println(Math.abs(-3));//绝对值  3
        System.out.println(Math.sqrt(36));//开平方 6
        System.out.println(Math.max(1, 3));//最大值 3
        System.out.println(Math.min(2, 3));//最小值 2
    }
}