莫尔斯到英语程序中的 Java 输出不正确

Question

这是我的摩尔斯电码到英语，反之亦然：

1. 在摩尔斯电码中，| 代表空格。
2. 在摩尔斯电码中，空格代表新字母或数字。

我的代码编译正确，但输出(运行后(不正确。

// 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 == "Morse Code")
toEnglish(amountUnit1);
else if (unit1 == "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 + ".");
}
}

我的输出是这样的：

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
Invalid data. Enter 'Morse Code' or 'English' without the single quotes.

它不会转到正确的 if-else 分支。它不是转到 unit1 == "英语"，而是转到无效数据的最后一个其他位置。

另外，对于toEnglish方法中的for循环，我应该如何设置i2？我需要i/2，但前提是第一个字符不是空格。

Answer 1

创建翻译后的字符串时，应使用以下字符串，而不是不允许赋值的charAt() =：

StringBuilder bob = new StringBuilder();
for (...){
if (...){
bob.append(character);
}
}
String english = bob.toString();

此外，i2将永远等于0.

这里还有许多其他小错误。继续调试，您最终将解决所有问题。

Answer 2

morse.charAt(i)

是一个函数，不能站在赋值的左侧。如果需要替换字符，请先将字符串转换为字符数组：

char[] english = morse.toCharArray();
english[i] = '|';

然后，如果需要，您可以在完成后转换回字符串(new String(myArray)(。阅读有关字符串的信息。

这就是错误的原因。当您逐个构建答案字符时，最合理的方法是通过StringBuilder，正如@Milk所建议的那样。与数组不同，StringBuilder知道如何增长，您在创建它时不需要指定大小。

Answer 3

还有另一个错误

Project1_szhu1249322.java：67：错误：不兼容的类型：字符无法转换为字符串 莫尔斯电码[i2] = english.charAt(i(;

morseCode[i2]返回String，而english.charAt(i)返回基元类型char。更改为morseCode[i2] = String.valueOf(english.charAt(i));以将它们都带到字符串