java.math包中常用的方法
1.Math.floor():向下取整(但结果是小数):
public class TestDemo1 {
public static void main(String[] args) {
System.out.println(Math.floor(11.5));
System.out.println(Math.floor(11.6));
System.out.println(Math.floor(11.4));
System.out.println(Math.floor(-11.5));
System.out.println(Math.floor(-11.6));
System.out.println(Math.floor(-11.4));
}
}
2.Math.abs():绝对值
public class TestDemo1 {
public static void main(String[] args) {
System.out.println(Math.abs(11.5));
System.out.println(Math.abs(11));
System.out.println(Math.abs(-11.5));
System.out.println(Math.abs(-11));
}
}
3.Math.pow(a,b):幂函数,a的b次方;
public class TestDemo1 {
public static void main(String[] args) {
System.out.println(Math.pow(2,3));
System.out.println(Math.pow(2.0,3));
System.out.println(Math.pow(2,3.0));
System.out.println(Math.pow(2.0,3.0));
}
}
4.Math.sqrt():算术平方根;(结果是double)
public class TestDemo1 {
public static void main(String[] args) {
System.out.println(Math.sqrt(8));
System.out.println(Math.sqrt(8.0));
System.out.println(Math.sqrt(9));
System.out.println(Math.sqrt(9.0));
}
}
5.- Math.max():最大值;Math.min():最小值;
public class TestDemo1 {
public static void main(String[] args) {
System.out.println(Math.max(2,5));
System.out.println(Math.max(2.0,5));
System.out.println(Math.max(2,5.0));
System.out.println(Math.max(2.0,5.0));
}
}
6.Math.round()四舍五入
- 规律;und(1.5) == 2;因为round对于正数是四舍五入的,对于负数:规律就是离谁近就是,比如-11.5,-11.4离-11最近就是-11,而-11.6离开-12近,就是-12;
public class TestDemo1 {
public static void main(String[] args) {
System.out.println(Math.round(1.5));
System.out.println(Math.round(1.6));
System.out.println(Math.round(1.4));
System.out.println(Math.round(-1.5));
System.out.println(Math.round(-1.6));
System.out.println(Math.round(-1.7));
}
}