我正在研究摩尔斯电码到英语的java代码(下图(，其中|在莫尔斯代表字母和数字之间的空格，莫尔斯中的空格代表2个字母或数字之间的空格。例如，"成为" = "- --- |-... ."在莫尔斯。
// Import Scanner.
import java.util.Scanner;
public class Project1_szhu1249322
{
public static void main(String[] args)
{
Scanner input = new Scanner (System.in);
System.out.println("Would you like to translate 'Morse Code' to English, or 'English' to Morse code? (Enter 'Morse Code' or 'English'.)");
String unit1 = input.nextLine();
System.out.println("Enter a string of " + unit1 + " characters (for English, numbers and letters, only): ");
String amountUnit1 = input.nextLine();
if (unit1.equals("Morse Code"))
toEnglish(amountUnit1);
else if (unit1.equals("English"))
toMorseCode(amountUnit1);
else
System.out.println("Invalid data. Enter 'Morse Code' or 'English' without the single quotes.");
}
public static void toMorseCode(String english)
{
// Declare variables, arrays, and strings.
int i = 0;
int l = english.length();
int i2 = 2 * i;
String[] lowerAlphabet = {"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"};
String[] upperAlphabet = {"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"};
String[] morseCode = {".-", "-...", "-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--..",".----","..---","...--","....-",".....","-....","--...","---..","----.","-----"};
morseCode[i] = lowerAlphabet[i];
StringBuilder morseBuilder = new StringBuilder();
// for loops and if statements for result.
for (i = 0; i < l; i++)
{
i2 = 2 * i;
if (english.charAt(i) != ' ')
morseBuilder.append(morseCode[i2]);
else
morseBuilder.append('|');
if (morseBuilder.charAt(i - 1) != ' ' && morseBuilder.charAt(i + 1) != 0)
morseBuilder.append(' ');
}
morseCode[i] = upperAlphabet[i];
// for loops and if statements for result.
for (i = 0; i < l; i++)
{
i2 = 2 * i;
if (english.charAt(i) != ' ')
morseBuilder.append(morseCode[i2]);
else
morseBuilder.append('|');
if (morseBuilder.charAt(i - 1) != ' ' && morseBuilder.charAt(i + 1) != 0)
morseBuilder.append(' ');
}
// Display results.
System.out.println("The corresponding Morse code is " + morseBuilder + ".");
}
public static void toEnglish(String morse)
{
// Declare variables, arrays, and strings.
int i = 0;
int l = morse.length();
int i2 = i / 2;
String[] lowerAlphabet = {"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"};
String[] upperAlphabet = {"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"};
String[] morseCode = {".-", "-...","-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--..",".----","..---","...--","....-",".....","-....","--...","---..","----.","-----"};
morseCode[i] = upperAlphabet[i];
String english;
StringBuilder englishBuilder = new StringBuilder();
// for loops and if statements for result.
for (i = 0; i < l; i++)
{
i2 = i / 2;
if (morse.charAt(i) == '|')
{
englishBuilder.append(' ');
}
else
englishBuilder.append(morseCode[i2]);
}
morseCode[i] = lowerAlphabet[i];
// for loops and if statements for result.
for (i = 0; i < l; i++)
{
i2 = i / 2;
if (morse.charAt(i) == '|')
{
englishBuilder.append(' ');
}
else
englishBuilder.append(morseCode[i2]);
}
// Display results.
System.out.println("The corresponding English is " + englishBuilder + ".");
}
}
我收到此错误：
Would you like to translate 'Morse Code' to English, or 'English' to Morse code? (Enter 'Morse Code' or 'English'.)
English
Enter a string of English characters (for English, numbers and letters, only):
to be
Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: -1
at java.lang.AbstractStringBuilder.charAt(AbstractStringBuilder.java:237)
at java.lang.StringBuilder.charAt(StringBuilder.java:76)
at Project1_szhu1249322.toMorseCode(Project1_szhu1249322.java:42)
at Project1_szhu1249322.main(Project1_szhu1249322.java:16)
我不明白为什么它给我这个错误消息。
另外(问题2(，我应该使用什么i2值？ i/2仅适用于i(当第一个字符不是空格时。帮助？？？
您在i==0时morseBuilder.charAt(i - 1)失败
您的代码有多个风险点。i=0此代码时，您将收到异常charAt(i - 1). 同样在循环完成后的函数toEnglish中，您将具有i等于l的值，因此，如果您的morse字符串的长度>长度为morseCode或lowerAlphabet，则下一行morseCode[i] = lowerAlphabet[i];将导致异常
使用地图将字母"A"、"B"等映射到它们的莫尔斯对应部分，反之亦然，将莫尔斯语映射到英语。这使您知道在两者之间进行转换时使用什么。请尝试以下操作并对其进行修改以满足您的需求。
public static void main(String[] args) throws IOException
{
String userInput = "Hello World";
String converted = ConvertEnglishToMorseCode(userInput);
System.out.println(userInput + " in Morse Code is " + converted);
System.out.println(converted + " in English is " + ConvertMorseCodeToEnglish(converted));
} //end main
public static String ConvertMorseCodeToEnglish(String input)
{
String[] upperAlphabet = {"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"};
String[] morseCode = {".-", "-...", "-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--..",".----","..---","...--","....-",".....","-....","--...","---..","----.","-----"};
HashMap<String, String> morseToEnlgish = new HashMap<>();
for(int i = 0; i < upperAlphabet.length; i++)
morseToEnlgish.put(morseCode[i], upperAlphabet[i]);
String morseToEnglish = "";
String[] morseSplit = input.split(" ");
for(int i = 0; i < morseSplit.length; i++)
{
morseToEnglish += morseToEnlgish.containsKey(morseSplit[i]) ? morseToEnlgish.get(morseSplit[i]) : " ";
}
return morseToEnglish;
}
public static String ConvertEnglishToMorseCode(String input)
{
String[] upperAlphabet = {"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"};
String[] morseCode = {".-", "-...", "-.-.","-..",".","..-.","--.","....","..",".---","-.-",".-..","--","-.","---",".--.","--.-",".-.","...","-","..-","...-",".--","-..-","-.--","--..",".----","..---","...--","....-",".....","-....","--...","---..","----.","-----"};
HashMap<String, String> englishToMorse = new HashMap<>();
for(int i = 0; i < upperAlphabet.length; i++)
englishToMorse.put(upperAlphabet[i], morseCode[i]);
String[] letters = input.toUpperCase().split("");
String englishToMorseWord = "";
for(int i = 0; i < letters.length; i++)
{
englishToMorseWord += englishToMorse.containsKey(letters[i]) ? englishToMorse.get(letters[i]) : "|";
if(i < letters.length - 1)
englishToMorseWord += " ";
}
return englishToMorseWord;
}
输出
Hello World in Morse Code is .... . .-.. .-.. --- | .-- --- .-. .-.. -..
.... . .-.. .-.. --- | .-- --- .-. .-.. -.. in English is HELLO WORLD
请注意两者之间的转换略有不同。对于英语，我们围绕"进行拆分以单独获取每个字符并使用映射。为了将莫尔斯电码转换为英语，我们围绕" "进行拆分，因为我假设提供给您的摩尔斯电码中的字母采用将英语单词转换为摩尔斯电码时输出的格式，空格分隔。最后，每当我们从英语到摩尔斯电码并且我们没有映射时，我们在从摩尔斯电码到英语时填写"|"和"。
祝你好运！