java语言的科学与艺术-PigLatin.java 

 1 /*
 2 * File: PigLatin.java
 3 * --------------
 4 * This file takes a line of text and converts each word into Pig Latin.
 5 * The rules for forming Pig Latin words are as follows:
 6 * - If the word begins with a vowel, add "way" to the end of the word.
 7 * - If the word begins with a consonant, extract the set of consonants up
 8 * to the first vowel, move that set of consonants to the end of the word,
 9 * and add "ay".
10 */
11 
12 import acm.program.*;
13 import java.util.*; // for the StringTokenizer class
14 public class PigLatin extends ConsoleProgram {
15 public void run(){
16 println("This program translates a line into Pig Latin,");
17 String line = readLine("Enter a line: ");
18 println(translateLine(line));
19 }
20 /* Translates a line to Pig Latin, word by word */
21 private String translateLine(String line){
22 String result = "";
23 StringTokenizer tokenizer = 
24 new StringTokenizer(line, DELIMITERS, true);
25 while(tokenizer.hasMoreTokens()) {
26 String token = tokenizer.nextToken();
27 if (isWord(token)){
28 token = translateWord(token);
29 }
30 result += token;
31 }
32 return result;
33 }
34 /* Translates a word to Pig Latin and returns the translated word */
35 private String translateWord(String word) {
36 int vp = findFirstVowel(word);
37 if(vp == -1){
38 return word;
39 } else if (vp == 0){
40 return word + "way";
41 } else {
42 String head = word.substring(0, vp);
43 String tail = word.substring(vp);
44 return tail + head + "ay";
45 }
46 }
47 
48 /* Returns the index of the first vowel in the word (-1 if none) */
49 private int findFirstVowel(String word) {
50 for(int i = 0; i < word.length(); i++) {
51 if(isEnglishVowel(word.charAt(i))) return i;
52 }
53 return -1;
54 }
55 
56 /* Returns true if the character is a vowel */
57 private boolean isEnglishVowel(char ch) {
58 switch (Character.toLowerCase(ch)) {
59 case 'a': case 'e': case 'i': case 'o': case 'u':
60 return true;
61 default:
62 return false;
63 }
64 }
65 
66 /* Returns true is token is a "word" (all character are letters) */
67 private boolean isWord(String token) {
68 for (int i = 0; i < token.length(); i++) {
69 char ch = token.charAt(i);
70 if(!Character.isLetter(ch)) return false;
71 }
72 return true;
73 }
74 
75 /* Defines the characters that delimit a token */
76 private static final String
77 DELIMITERS = "!@#$%^&*()_-+={[}]:;\"'<,>.?/~`|\\ ";
78 }

 

posted on 2012-12-31 18:03  mybluecode  阅读(467)  评论(0)  编辑  收藏  举报