6

我正在尝试编写一个程序，它将字母表中的任何字母（大写或小写）转换为 Phontic 字母表。例如，如果我输入“A”或“a”，我的程序会给我（将其更改为）“Alpha”。我对这个和 switch 语句做了很多研究，但我一直卡住。我意识到我不能在扫描仪中使用“char”。但是，当我将 'char' 更改为 'String' 时，我的 switch 语句会变得混乱（特别是我的代码中的toUpperCase有下划线。我看不到我的错误。这是我到目前为止所做的：

import java.util.Scanner;
public class PhoneticTranslate {
public static void main(String[] args) {


char letter;
String phonetic;

Scanner kb = new Scanner(System.in);


System.out.print("Please enter a letter: ");
letter = kb.next();

switch(Character.toUpperCase(letter))
{
case 'A':
    phonetic = "Alpha";
break;
case 'B':
    phonetic = "Bravo";
    break;
case 'C':
    phonetic = "Charlie";
    break;
case 'D': 
    phonetic = "Delta";
    break;
case 'E':
    phonetic = "Echo";
    break;
case 'F':
    phonetic = "Foxtrot";
    break;
case 'G':
    phonetic = "Golf";
    break;
case 'H':
    phonetic = "Hotel";
    break;
case 'I':
    phonetic = "India";
    break;
case 'J':
    phonetic = "Juliet";
case 'K':
    phonetic = "Kilo";
    break;
case 'L':
    phonetic = "Lima";
    break;
case 'M':
    phonetic = "Mike";
    break;
case 'N':
    phonetic = "November";
    break;
case 'O':
    phonetic = "Oscar";
    break;
case 'P':
    phonetic = "Papa";
    break;
case 'Q':
    phonetic = "Quebec";
    break;
case 'R':
    phonetic = "Romeo";
    break;
case 'S':
    phonetic = "Sierra";
    break;
case 'T':
    phonetic = "Tango";
    break;
case 'U':
    phonetic = "Uniform";
    break;
case 'V':
    phonetic = "Victor";
    break;
case 'W':
    phonetic = "Whiskey";
    break;
case 'X':
    phonetic = "X-Ray";
    break;
case 'Y':
    phonetic = "Yankee";
    break;
case 'Z':
    phonetic = "Zulu";
    break;


}

}
}
4

4 回答 4

6

您需要使用 charAt。Scanner.next()方法String不返回char，因此您需要转换String为char

letter = kb.next().charAt(0);
于 2012-10-17T16:08:46.230 回答
3

您可以更好地创建一个Map<Character, String>来避免自己26 cases在 switch 中写入。这样你只需要get一个特定字符的字符串。

Map<Character, String> mapping = new HashMap<Character, String>();
mapping.put('a', "Alpha");
mapping.put('b', "Beta");
..  And so on..

当然你必须承担初始化的负担Map，但它会比一个Mess更好switch - case

好处是，你还可以populate从Map一些file以后。

然后，当您从扫描仪读取字符时，用于charAt(0)获取第一个字符，因为Scanner.next()返回一个字符串：-

letter = kb.next().charAt(0);

// Fetch the Phonetic for this character from `Map`
phonetic = mapping.get(letter);
于 2012-10-17T16:11:56.090 回答
1 
String letter;
String phonetic;
Map<String,String> codes = new HashMap<String,String>();
codes.put("A","Alpha");
codes.put("B","Bravo");
codes.put("C","Charlie");
codes.put("D","Delta");
    // not showing all assignments to make it shorter
codes.put("W","Whiskey");
codes.put("X","X-Ray");
codes.put("Y","Yankee");
codes.put("Z","Zulu");

Scanner kb = new Scanner(System.in);

System.out.print("Please enter a letter: ");
letter = kb.next().toUpperCase();

phonetic = codes.get(letter);

if (phonetic == null) {
    System.out.println("bad code : " + letter);
} else {
    System.out.println("Phonetic: " + phonetic);
}
于 2012-10-17T16:22:49.323 回答
0

该Scanner.next()方法返回 a String，而不是 a ，因此您需要在将其与 s 进行比较之前char获取该Stringusing的第一个字符。String.charAt(...)char

于 2012-10-17T16:11:57.257 回答