java - 如何创建替换关键字密码

Question

我正在尝试开发一种替换密码，它使用关键字来创建新的密码字母表。我是 Java 新手(我相信你会知道!)并且我正在找到它很难理解我需要做什么的代码。

我的理解如下:

例如，如果关键字是 javben，我应该首先在纯文本字符串数组中查找“j”的索引，即 9。然后我想移动纯文本[9 ] 到 cipherText[0] 中，并将每个其他元素移动 1。因此，第一遍将导致:

cipherText[] = {"j","a","b","c","d","e","f","g","h","i","k","l","m","n","o","p","q","r","s","t","u","v","w","r","x","y","z"}

然后我会找到“a”，它已经在它应该在的位置了，所以我需要考虑到这一点，而不是以某种方式移动它。下一个字符是“v”，因此该过程将继续。

在改变密码中的所有内容后，我最终应该得到:

plainText []= {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","r","x","y","z"}
cipherText[]= {"j","a","v","b","e","n","c","d","f","g","h","i","k","l","m","o","p","q","r","s","t","u","w","r","x","y","z"}

正如您所看到的，我相当确定我了解要经历的过程，但是我真的很难理解所需的代码。请帮助!

import java.util.Scanner;
import java.io.*;
/**
* This program uses a keyword for a simple substitution cipher.
* 
* @author Bryan
* @version Programming Project
*/

public class Cipher
{
// The main method removes duplicate characters in a word input by the user.
public static void main(String[] args) throws IOException
{
    // Creatae a new scanner object for keyboard input
    Scanner keyboard = new Scanner(System.in);

    // prompt the user to enter a word
    System.out.println("Please enter your keyword: ");
    // and get their input
    String input = keyboard.nextLine();
    // the keyword will be built up here
    String keyword = "";

    while(input.length() > 0) 
    {
        // get the first letter
        char letter = input.charAt(0);
        // if the letter is not already in the output
        if (keyword.indexOf(letter) == -1)
        {
            // add it to the end
            keyword = keyword + letter;
        }

        // that letter is processed : discard it
        input = input.substring(1);
    }

    //this is just to confirm the duplicate letters in the keyword are removed
    System.out.println(keyword); 
    getFile();

}

/**
 * This asks the user to specify a filename which is then 
 * read into the program for enciphering
 */

public static void getFile()throws IOException
{
    // Creatae a new scanner object for keyboard input
    Scanner keyboard = new Scanner(System.in);

    // Get the file name
    System.out.println("Enter the file name: ");
    String filename = keyboard.nextLine();

    //Open the file
    File file = new File(filename);
    Scanner inputFile = new Scanner(file);

    // Read the lines from the file until no more are left
    while (inputFile.hasNext())
    {
        //Read the next line
        String allText = inputFile.nextLine();

        // Display the text
        System.out.println(allText);
    }




    //Close the file
    inputFile.close();

}

public static void alphabet()
{
    String[] plainText =     {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
    String[] cipherText = {"a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"};
}
}

Answer 1

这个很简单，只需设置一个函数，对于关键字中的每个字母，只需将其从字母表数组中取出，然后将两个数组与开头的字母数组和不带字母的字母表相加。后面的那些字母。例如:

String[] cipherKeyWord(String keyWord, String[] alphabet){
    ArrayList<String> finalCipher = (ArrayList) Arrays.asList(keyWord.split("(?!^)")); 
    //^ This splits it into a string of every word using regular expressions

    ArrayList<String> newAlphabet = (ArrayList) Arrays.asList(alphabet);

    newAlphabet.removeAll(finalCipher);

    finalCipher.addAll(newAlphabet);

    return finalCipher.toArray(new String[finalCipher.size()]);
}