不耻下问：Java语言求绝对值，不使用if语句和函数，到底怎么实现呢

不耻下问：Java语言求绝对值，不使用if语句和函数，到底怎么实现呢

用三目运算符即可。

class Test {
    public static void main(String[] args) {
        int a = 8;
        double b = -5.0;
        System.out.println(a < 0 ? -a : a);
        System.out.println(b < 0 ? -b : b);
    }
}

输出:
8
5.0

参考Math.abs的实现。
/**
* Returns the absolute value of an {@code int} value.
* If the argument is not negative, the argument is returned.
* If the argument is negative, the negation of the argument is returned.
*
*

Note that if the argument is equal to the value of
* {@link Integer#MIN_VALUE}, the most negative representable
* {@code int} value, the result is that same value, which is
* negative.
*
* @param a the argument whose absolute value is to be determined
* @return the absolute value of the argument.
*/
public static int abs(int a) {
return (a < 0) ? -a : a;
}

import java.util.Scanner;

public class Day_10 {
    public static void main(String[] args) {

                    Scanner input=new Scanner(System.in);
                    System.out.println("请输入一个整数：");
                    int number=input.nextInt();

                    //数字方法：用三目运算符判断number是否大于零大于零直接输出，小于零乘以-1以便得到一个正数。
                    System.out.print(number+" 的绝对值为：");
                    System.out.println(number>0?number:number*-1);

                    //字符串方法：用Sting里的replace()方法代替掉“-”就可以了。
                    String str=""+number;
                    str=str.replace("-","");
                    int result=Integer.parseInt(str);
                    System.out.println(number+" 的绝对值为："+result);

    }


}

结果:
请输入一个整数：
-5954
-5954 的绝对值为：5954
-5954 的绝对值为：5954