Java 数学工具类Math
数学工具类Math
- java.util.Math 类是数学相关的工具类,里面提供了大量的静态方法,完成与数学运算相关的操作
public static double abs(double num)
:获取绝对值public static double ceil(double num)
:向上取整public static double floor(double num)
:向下取整public static long round(double num)
:四舍五入
代码:
public class a32_数学工具类Math {
public static void main(String[] args) {
// 绝对值
System.out.println(Math.abs(-2));
System.out.println(Math.abs(2));
System.out.println(Math.abs(0));
System.out.println("---------");
// 向上取整
System.out.println(Math.ceil(8.2));
System.out.println(Math.ceil(8.98));
System.out.println(Math.ceil(2.3));
System.out.println("---------");
// 向下取整
System.out.println(Math.floor(9.4));
System.out.println(Math.floor(9.42));
System.out.println(Math.floor(4.65));
System.out.println("---------");
// 四舍五入
System.out.println(Math.round(5.6));
System.out.println(Math.round(5.3));
System.out.println(Math.round(4.9));
System.out.println("---------");
// 圆周率
System.out.println(Math.PI);
}
}
练习
找出-10.8到5.9中绝对值大于6或小于2.1的整数
public class a33_小学数学真题 {
public static void main(String[] args) {
double num01 = Math.ceil(-10.8);
int num02 = (int)num01;
int a = 0;
for (int i = num02; i <= 5.9; i++){
if (Math.abs(i) > 6 || Math.abs(i) < 2.1) {
a++;
}
}
System.out.println(a);
}
}
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