无法使用Java将int转换为char [英] can't cast int to char with Java

问题描述

我被分配了一个生成介于1到26之间的随机数，然后将该数字转换为从 a到 z的字母的任务。
随机生成的部分看起来不错，但是当我尝试将数字强制转换为char时，我只会得到一个空的方形框！
为什么？

I was given an assignment to generate a random number between 1 to 26 then convert that number to a letter from 'a' to 'z'. the random generating part looks fine but when I try to cast the number to char, I would just get an empty square-like box! why is that?

    import java.util.Random;
    public class NumbersToLetters 
    {
        public static void main(String[] args) 
        {
            Random n;
            int num;
            n=new Random();
    //generating a random number from 1 to 26
            num=Math.abs(((n.nextInt())%26)+1); 
    //cast from int to char
            char myChar = (char) num; 
            System.out.println ("Number - " + num); 
            System.out.println ("Char - " + myChar);

   //I'm sure that my answer is right but no matter what I do,
   //it won't output a letter, all I get is a square-like box..
        }
    }

推荐答案

您生成的数字介于1到27（含）之间。如果您查看这些字符所对应的，您会发现它们实际上都不是可打印的。

You're generating a number between 1 and 27 (inclusive). If you look at what those characters correspond to, you'll see that none of them are actually printable.

您应使用 +'a'而不是 +1

n.nextInt(26) + 'a';

这将为您提供正确的偏移量（恰好是97）以查找小写字母。

This will give you the correct offset (which happens to be 97) to find the lower case letters.

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