Java-函数似乎弄乱了控制台，调用该函数后不会打印任何内容

Question

我被要求编写一个方法来接收扫描仪，并返回一个排序的单词数组，其中仅包含字母，没有重复(长度不超过 3000)。然后，我被要求编写一个方法来检查给定的词汇表中是否包含某个给定的字符串。我使用了简单的二分查找方法。 这就是我所做的:

public static String[] scanVocabulary(Scanner scanner){       
		String[] array= new String[3000];
		int i=0;
		String word;
		while (scanner.hasNext() && i<3000) {
			word=scanner.next();
			if (word.matches("[a-zA-Z]+")){
				array[i]=word.toLowerCase();
				i++;
			}
		}int size=0;
		while (size<3000 && array[size]!=null ) {
			size++;
		}
		String[] words=Arrays.copyOf(array, size);
		if (words.length==0 || words.length==1) {
			return words;
		}
		else {
			Arrays.sort(words);
			int end= removeDuplicatesSortedArr(words);
			return Arrays.copyOf(words, end);
		}

	}
	
	private static int removeDuplicatesSortedArr(String[] array) { //must be a sorted array. returns size of the new array
		int n= array.length;
		int j=0;
		for (int i=0; i<n-1; i++) {
			if (!array[i].equals(array[i+1])) {
				array[j++]=array[i];
			}
		}
		array[j++]=array[n-1];
		return j;
	}
	
	public static boolean isInVocabulary(String[] vocabulary, String word){ 
		//binary search
		int n=vocabulary.length;
		int left= 0;
		int right=n-1;
		while (left<=right) {
			int mid=(left+right)/2;
			if (vocabulary[mid].equals(word)){
				return true;
			}
			else if (vocabulary[mid].compareTo(word)>0) {
				right=mid-1;
			}else {
				right=mid+1;
			}
		}
		return false;
	}

尝试以下代码时:

public static void main(String[] args) {

        String vocabularyText = "I look at the floor and I see it needs sweeping while my guitar gently weeps";
        Scanner vocabularyScanner = new Scanner(vocabularyText);
        String[] vocabulary = scanVocabulary(vocabularyScanner);
        System.out.println(Arrays.toString(vocabulary));

        boolean t=isInVocabulary(vocabulary, "while");
        System.out.println(t);
        System.out.println("123");

    }

我什么也没得到，除了-

[and, at, floor, gently, guitar, i, it, look, my, needs, see, sweeping, the, weeps, while]

没有其他内容被打印出来或返回。这两个功能似乎单独工作得很好，所以我不明白我做错了什么。 我很高兴听到您的想法，提前致谢:)

Answer 1

这与控制台无关。您的 isInVocabulary 方法在此 block 中进入无限循环:

    if (!isInVocabulary(vocabulary, "while")) {
        System.out.println("Error");
    }

如果您通过 isInVocabulary 进行调试，您会看到在 while 循环迭代几次后，

left = 0;
right = 2;

mid = 1;

if (vocabulary[mid].equals(word)){
    // it doesn't
} else if (vocabulary[mid].compareTo("while") > 0) {
    // it doesn't
} else {
    right = mid + 1;
    // this is the same as saying right = 1 + 1, i.e. 2
}

所以你会永远循环。