Math里面提供了大量静态方法,  完成与数学运算相关的操作.

public static double abs(double num):  取绝对值
public static double ceil(double num): 向上取整数
public static double floor(double num): 向下取整
public static long round(double num): 四舍五入
Math.PI  代表近似的圆周率   public static final double PI = 3.14159265358979323846;

Math里面提供了大量静态方法,  完成与数学运算相关的操作.

public static double abs(double num):  取绝对值
public static double ceil(double num): 向上取整数
public static double floor(double num): 向下取整
public static long round(double num): 四舍五入
Math.PI  代表近似的圆周率   public static final double PI = 3.14159265358979323846;