如何在Java中创建随机生成的字母 [英] how to create a random generated alphabet in Java

问题描述

试图为替换密码创建随机生成的字母.我的想法是这样的.

Looking to create a randomly generated alphabet for a substitution cipher. My idea was something like this.

        char randomChar = (char) (97 + r.nextInt(25));

但是，这将导致字母重复.遍历char数组并查看该字母是否已经存在似乎也是无效的.

However this will cause repetition of letters. Going through the char array and seeing if the letter is already present seems inefficient also.

edit:我的要求太含糊了，现在看看.这是我要解决的完整问题.字母还必须包含空格键字符，例如''.

edit: I was too vague in my request and see this now. Here is the full question I am trying to solve. The alphabet must also contain the space button character e.g ' '.

编写一个Java程序，该程序使用替代密码(将纯文本字母随机分配给密文字母)将(用户输入的)纯文本转换为密文.请注意，替换密码"将明文替换为密文.最常见的替换密码将明文的单个字符替换为预定义的密文单个字符(例如，纯文本字符"a"可能会替换为密文字符"q"，"b"可能会替换为"x"，"c"乘"k"，依此类推).每个纯文本字符应替换为不同的密文字符.作为解决方案的一部分，您必须至少编写和使用以下函数/方法:(i)createCipher()，它确定并返回从纯文本到密文的映射.每个纯文本字符('a'..'z'，'')必须随机分配一个密文字符；

Write a Java program which converts (user entered) plain text to cipher text using a substitution cipher (in which plain text letters are randomly assigned to cipher text letters). Note that a Substitution Cipher replaces plaintext with cipher-text. The most common substitution ciphers replace single characters of plaintext with predefined single characters of cipher-text (e.g. the plain-text character `a' might be replaced by cipher text character 'q', 'b' might be replaced by 'x', 'c' by 'k' and so on). Each plain-text character should be replaced by a different cipher-text character. As part of your solution you must write and use at least the following functions/methods: (i) createCipher() which determines and returns the mapping from plain text to cipher text. Each plain text character ('a' .. 'z', ' ') must be randomly assigned a cipher-text character;

推荐答案

如果您想对字母进行随机播放，可以使用 Collections.shuffle(..)方法.像这样:

If you want to shuffle an alphabet you can use the Collections.shuffle(..) metode. Somethink like this:

public static void main(String[] args) {
    char[] alphabet = "abcdefghijklmnopqrstuvwxyz".toCharArray();
    char[] randomAlphabet = new char[alphabet.length];

    // Copy to a List
    List<Character> list = new ArrayList<Character>();
    for (char c : alphabet) {
        list.add(c);
    }

    // shuffle it       
    Collections.shuffle(list);

    // Copy it back to an array
    for (int i = 0; i < list.size(); i++) {
        randomAlphabet[i] = list.get(i);
    }

    System.out.print("Random alphabet: ");
    for (int i = 0; i < randomAlphabet.length; i++) {
        System.out.print(" " + randomAlphabet[i]);
    }
}

在我运行它时会给出以下信息:

That gives this when I run it:

Random alphabet:  j b w q o c r f z k g n p a u s i d m y h v e l x t

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