摩爾斯電碼轉換使用Java

Question

我想了解Java中的hashmaps和2D數組。我們有一個任務，因爲有一個掃描儀接受一個字符串並將其轉換爲莫爾斯電碼。我們使用的代碼基於一個充滿if語句的方法，但我想了解如何使用列表，hashmaps或2D數組來做類似的事情。我的代碼如下：

import java.util.*; 

public class MorseConversion 
{ 


public static void main(String[] args) 
{ 

    Scanner userInput = new Scanner(System.in); 
    System.out.println("Please enter a phrase to convert to morse code: "); 
    String userString = userInput.nextLine(); 
    System.out.println(""); 
    System.out.println(stringConvert(userString)); 
} 


public static String stringConvert(String userString) 
{ 
    String currentChar; 
    String getMorseChar; 
    String convertedString = ""; 

    for (int i = 0; i < userString.length(); i++) 
    { 
     //Get character at i position 
     currentChar = userString.charAt(i) + ""; 

     //convert character to morse code 
     getMorseChar = convert(currentChar); 

     //seperate words with the | symbol 
     if (getMorseChar.equals(" ")) 
     { 
      convertedString = convertedString + " | "; 
     } 

     else 
     { 
      //concat the converted letter 
      convertedString = convertedString + getMorseChar; 

      //Add a space between each letter 
      if (!getMorseChar.equals(" ")) 
      { 
       convertedString = convertedString + " "; 
      } 
     }   
    } 

    return convertedString; 

} 
public static String convert (String toEncode) 
    { 
     String morse = toEncode; 

     if (toEncode.equalsIgnoreCase("a")) 
      morse = ".-"; 
     if (toEncode.equalsIgnoreCase("b")) 
      morse = "-..."; 
     if (toEncode.equalsIgnoreCase("c")) 
      morse = "-.-."; 
     if (toEncode.equalsIgnoreCase("d")) 
      morse = "-.."; 
     if (toEncode.equalsIgnoreCase("e")) 
      morse = "."; 
     if (toEncode.equalsIgnoreCase("f")) 
      morse = "..-."; 
     if (toEncode.equalsIgnoreCase("g")) 
      morse = "--."; 
     if (toEncode.equalsIgnoreCase("h")) 
      morse = "...."; 
     if (toEncode.equalsIgnoreCase("i")) 
      morse = ".."; 
     if (toEncode.equalsIgnoreCase("j")) 
      morse = ".---"; 
     if (toEncode.equalsIgnoreCase("k")) 
      morse = "-.-"; 
     if (toEncode.equalsIgnoreCase("l")) 
      morse = ".-.."; 
     if (toEncode.equalsIgnoreCase("m")) 
      morse = "--"; 
     if (toEncode.equalsIgnoreCase("n")) 
      morse = "-."; 
     if (toEncode.equalsIgnoreCase("o")) 
      morse = "---"; 
     if (toEncode.equalsIgnoreCase("p")) 
      morse = ".--."; 
     if (toEncode.equalsIgnoreCase("q")) 
      morse = "--.-"; 
     if (toEncode.equalsIgnoreCase("r")) 
      morse = ".-."; 
     if (toEncode.equalsIgnoreCase("s")) 
      morse = "..."; 
     if (toEncode.equalsIgnoreCase("t")) 
      morse = "-"; 
     if (toEncode.equalsIgnoreCase("u")) 
      morse = "..-"; 
     if (toEncode.equalsIgnoreCase("v")) 
      morse = "...-"; 
     if (toEncode.equalsIgnoreCase("w")) 
      morse = ".--"; 
     if (toEncode.equalsIgnoreCase("x")) 
      morse = "-..-"; 
     if (toEncode.equalsIgnoreCase("y")) 
      morse = "-.--"; 
     if (toEncode.equalsIgnoreCase("z")) 
      morse = "--.."; 
     if (toEncode.equalsIgnoreCase("0")) 
      morse = "-----"; 
     if (toEncode.equalsIgnoreCase("1")) 
      morse = ".----"; 
     if (toEncode.equalsIgnoreCase("2")) 
      morse = "..---"; 
     if (toEncode.equalsIgnoreCase("3")) 
      morse = "...--"; 
     if (toEncode.equalsIgnoreCase("4")) 
      morse = "....-"; 
     if (toEncode.equalsIgnoreCase("5")) 
      morse = "....."; 
     if (toEncode.equalsIgnoreCase("6")) 
      morse = "-...."; 
     if (toEncode.equalsIgnoreCase("7")) 
      morse = "--..."; 
     if (toEncode.equalsIgnoreCase("8")) 
      morse = "---.."; 
     if (toEncode.equalsIgnoreCase("9")) 
      morse = "----."; 
     if (toEncode.equalsIgnoreCase(".")) 
      morse = ".-.-"; 
     if (toEncode.equalsIgnoreCase(",")) 
      morse = "--..--"; 
     if (toEncode.equalsIgnoreCase("?")) 
      morse = "..--.."; 

     return morse; 
    } 

} 

我這樣做是出於好奇。我已經讓我感到震驚，像這樣的冗餘是一個巨大的禁忌。提前致謝！

Answer 1

更簡單的方法是使用初始值設定項將字符加載到使用字母作爲關鍵字的哈希映射中。然後當你的循環在你輸入字符串中的字符您簡單地做

你上課的時候做這樣的事情：

private static HashMap<String, String> codes = new HashMap<String, String>(); 
    static{ 
     codes.put("a", ".-"); 
     codes.put("b", "-..."); 
     bla bla bla 
    } 

然後在你的循環，你必須

//convert character to morse code 
     getMorseChar = convert(currentChar); 

你本來

getMorseChar = code.get(currentChar.toLowerCase()); 

不再討厭ELSEIF語句。

Answer 2

這裏是賦予2 d陣列清醒的認識優化的代碼

public class MorseCode { 
public static Scanner sc; 
public static void main(String args[]) throws IOException //Input Output Exception is added to cover the BufferedReader 
{ 
    int option = 0; 
    String sentence = "",answer = "",answer1 = ""; 
    char[] english = { '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', '1', '2', '3', '4', '5', '6', '7', '8', '9', '0', 
      ',', '.', '?' }; //Defining a Character Array of the English Letters numbers and Symbols so that we can compare and convert later 

    String[] morse = { ".-", "-...", "-.-.", "-..", ".", "..-.", "--.", "....", "..", 
       ".---", "-.-", ".-..", "--", "-.", "---", ".---.", "--.-", ".-.", 
       "...", "-", "..-", "...-", ".--", "-..-", "-.--", "--..", ".----", 
       "..---", "...--", "....-", ".....", "-....", "--...", "---..", "----.", 
       "-----", "--..--", ".-.-.-", "..--.." }; //Defining an Array of String to hold the Morse Code value of Every English Letter,Number and Symbol in the same order as that of the character Array 
    sc = new Scanner(System.in); 
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); 
    System.out.println(">>>>Welcome to MorseCode Software<<<<"); 
    System.out.println(""); 
    do 
    { 
    System.out.println("-->Enter the Option Corresponding to the Task you want to Perform "); 
    System.out.println("->1.Generate Morse Code<- OR ->2.Generate English Language<- OR ->3.Exit "); 
    System.out.print("->"); 
    while(!sc.hasNextInt()) //Repeat Until the next Item is an Integer i.e Until the Next Item is an Integer Keep on Repeating it 
    {//NOTE- The hasnext() function is also used when we are using the Iterator where the next input is always checked and then if it is valid it is allowed to be entered 
     System.out.println(""); 
     System.err.println("-->ERROR<-->Enter Digits Only<--"); 
     System.out.print("->"); 
     sc.next(); //Repeat and Discard the previous Inputs which are not valid 
    } 
    option = sc.nextInt(); 
    switch(option) 
    { 
    case 1: 
    { 
     System.out.println(""); 
     System.out.println("-->Enter the Sentence that you want to Transmit Using the Morse Code "); 
     System.out.print("->"); 
     sentence = br.readLine(); 
     System.out.println(""); 
     sentence = sentence.toLowerCase(); //Because morse code is defined only for the lower case letters and the numbers and the Symbols will remain the Same 
     char[] morsec = sentence.toCharArray(); 
     for(int i = 0; i < morsec.length;i++) //The loop will run till i is less than the number of characters in the Sentence because Every Character needs to Be Converted into the Respective Morse Code 
     {//For Every Letter in the User Input Sentence 
      for(int j = 0;j<english.length;j++) //For Every Character in the morsec array we will have to traverse the entire English Array and find the match so that it can be represented 
      { 
       if(english[j] == morsec[i]) //If the Character Present in English array is equal to the character present in the Morsec array then Only Execute 
       {//Always remember that the condition in the Inner loop will be the first to be Equated in the If Statement because that will change until the characters match 
        answer = answer + morse[j] + " "; //After Every Letter is generated in the Morse Code we will give a Space 
       } //Since the Letters in the English char and the symbols present in the morse array are at the Same Index 
      } 
     } 
     System.out.println("-->The Morse Code Translation is:- "); 
     System.out.print(">> "); 
     System.out.println(answer); 
     System.out.println(""); 
     break; 
    } 
    case 2: 
    { 
     System.out.println(""); 
     System.out.println("-->Enter the Morse Code and After Every Letter add Space in Between "); 
     System.out.print("-> "); 
     sentence = br.readLine(); 
     System.out.println(""); 
     String[] morsec = sentence.split(" "); //To use the split function to Convert Every Morse Code String as a Separate Entry in the STring array 
     for(int i = 0;i < morsec.length;i++) 
     {//For Every morse code Letter Entered 
     //Remember - We are Splitting on the Basis of the space  
      for(int j = 0;j < morse.length;j++) 
      { 
       if(morse[j].equals(morsec[i])) //When you are comparing the String you have to Do this and not == 
       { 
        answer1 = answer1 + english[j]; //Since the characters in the Morse array and the English Array are in the Same Index 
       } 
      } 
     } 
     System.out.println("-->The English Language Translation is:- "); 
     System.out.print(">> "); 
     System.out.println(answer1); 
     System.out.println(""); 
     break; 
    } 
    case 3: 
    { 
     System.out.println(""); 
     System.out.println(">>Thank you For Using this Service<<"); 
     System.out.println(""); 
     break; 
    } 
    default: 
    { 
     System.err.println("-->ERROR<-->Invalid Option Entered<--"); 
     System.out.println(""); 
     break; 
    } 
    } 
    } 
    while(option!=3); 
    } 

}

希望不存在混淆的代碼