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下面的程序应该这样做：

当用户输入时： The quick brown fox. Jumps over. The lazy dog.
它应该输出：God yzal eth. Revo spmuj. Xof nworb kciuq eht.

但是当用户输入时：The quick brown fox. Jumps over. The lazy dog.
它输出：xof nworb kciuq ehT. revo spmuJ . god yzal ehT .

所以这是我的代码：

import java.util.*;
public class Reverse {
public static void main( String args[] ) {
    String paragraph;
    Scanner input = new Scanner (System.in);

    System.out.print("Enter a paragraph: ");
    paragraph = input.nextLine();
    paragraph = paragraph.trim();
    StringTokenizer tokens = new StringTokenizer(paragraph, ".");
    while (tokens.hasMoreTokens()){
        String ss = tokens.nextToken();
        for (int i = ss.length() - 1; i>=0; i--) {
            System.out.print(ss.charAt(i));
        }
        System.out.print(". ");
    }
    System.out.println();
}
}

我也想到了这个：

import java.util.*;

public class Reverse{

    public static void main(String[] args) {
    String paragraph;
    Scanner input = new Scanner (System.in);

    System.out.print("Enter a paragraph: ");
    paragraph = input.nextLine();
    paragraph = paragraph.trim();

    StringTokenizer parWordTokenizer = null;
    StringTokenizer parDotTokenizer = null;
    int numParDotTokens = 0;
    int numParWordTokens = 0;

    parDotTokenizer = new StringTokenizer (paragraph, ".");
    parWordTokenizer = new StringTokenizer (paragraph);
    numParDotTokens = parDotTokenizer.countTokens();
    numParWordTokens = parWordTokenizer.countTokens();

    String[] sentences = new String[numParDotTokens];
    String[] words = new String[numParWordTokens];
    String[] characters = new String[5];

    for (int i=0; i<numParDotTokens; i++) {
        sentences[i] = parDotTokenizer.nextToken();
        System.out.print("S: "+sentences[i]+"\n");
        parWordTokenizer = new StringTokenizer (sentences[i]);
        numParWordTokens = parWordTokenizer.countTokens();
        while (parDotTokenizer.hasMoreTokens()){
            String ss = parDotTokenizer.nextToken();
            for (int k = ss.length() - 1; k>=0; k--) {
                System.out.print(ss.charAt(k));
            }
            System.out.print(". ");
        }
        for (int j=0; j<numParWordTokens; j++) {
            words[j] = parWordTokenizer.nextToken();
            System.out.print("W: "+words[j]+"\n");
            while (parWordTokenizer.hasMoreTokens()){
                String ss = parWordTokenizer.nextToken();
                for (int k = ss.length() - 1; k>=0; k--) {
                    System.out.print(ss.charAt(k));
                }
                System.out.print(". ");
            }
        }
        }
    } }

但 revo spmuJ . god yzal ehT . kciuq. nworb. xof. Exception in thread "main" java.util.NoSuchElementException at java.util.StringTokenizer.nextToken(Unknown Source) at ScrambleParagraph.main(Reverse.java:40) 请帮我解决它。几天来我一直在考虑正确的实现，但我是 Java 新手，所以至少现在我做不到。非常感谢你！

4

3 回答 3

1

这大致是我的做法：

public static void main(String[] args) {

    String paragraph;
    Scanner input = new Scanner(System.in);

    System.out.print("Enter a paragraph: ");
    paragraph = input.nextLine();
    paragraph = paragraph.trim();

    String reversedParagraph = new StringBuilder(paragraph)
            .reverse().toString().toLowerCase();

    StringBuilder out = new StringBuilder();
    for (String sentence : reversedParagraph.split(" *\\.")) {
        if (!sentence.equals("")) {
            sentence += ". ";
            out.append(Character.toUpperCase(sentence.charAt(0))
                    + sentence.substring(1));
        }
    }
    System.out.println(out.toString().trim());

}

给定输入："The quick brown fox. Jumps over. The lazy dog."

这会产生："God yzal eht. Revo spmuj. Xof nworb kciuq eht."

这似乎是你所要求的。

特殊成分是：StringBuilder.reverse()将字符串反转并 String.split(regex)根据正则表达式将字符串拆分为多个片段。在我颠倒它之后，我用它来遍历段落中的每个句子。

于 2012-07-22T08:45:41.103 回答
1

这样会简单得多。

public String inverse(String str) {
    StringBuffer strBuf= new StringBuffer(str.trim());
    return strBuf.reverse().toString();         
}
于 2014-02-06T18:35:27.777 回答
-2

用“。”分割输入怎么样？首先然后反转每个元素？

public class Reverse {

    public static void main(String[] args) {
        String input = "The quick brown fox. Jumps over. The lazy dog.";
        String[] sentences = input.split("\\.");
        StringBuilder result = new StringBuilder();
        for (int i = sentences.length - 1; i >= 0; i--) {
            String sentence = sentences[i];
            result.append(".").append(
                    new StringBuilder(sentence).reverse().toString());
        }
        System.out.println(result);
    }
}

输出：

.god yzal ehT .revo spmuJ .xof nworb kciuq ehT
于 2012-07-22T08:17:34.070 回答