Question

我正在用Java构建一个回文程序。分配是从文件中读取单词，确定文件中的单词是否是回文，并将结果发送到另一个文件。我有一切正常，但我的程序中唯一的问题是它只会读取第一个单词。我需要它来读取文件中的所有行。我的代码是：

import java.util.Scanner;
import java.io.*;

public class str1 {

    public static void main(String args[]) {
      try {

      String reverse = "";
      System.out.print("Enter the name of the input file: ");
      Scanner keyboard = new Scanner(System.in);
      String a = keyboard.nextLine();
      int length = a.length();
      File inFile = new File(a);
      Scanner fin = new Scanner(inFile);
      System.out.print("Enter name of the output file: ");
      String outFileName= keyboard.nextLine();
      File outFile = new File(outFileName);
      PrintWriter fout = new PrintWriter(outFile);
      while ( fin.hasNext(a) ) {
      for ( int i = length - 1; i >= 0; i-- )
     reverse = reverse + a.charAt(i);

  if (a.equals(reverse))
     fout.println("Entered string is a palindrome.");
  else
     fout.println("Entered string is not a palindrome.");
      }
      fin.close();
      fout.close();
      System.out.print("Done. See '" + outFileName + "'.");
      } catch (Exception e) {
          e.printStackTrace();
      }
    }
}

我试图将第23行中的while更改为“while（fin.hasNextLine（a））{”但我没有成功。我相信这就是为什么它不会读过第一行。非常感谢任何帮助。

Answer 1

这应该有效。您需要在检查输入文件的条件后添加h_vertices方法，实际处理它，并在读取后检查单词的长度：

import java.io.File; import java.io.PrintWriter; import java.util.Scanner;

nextLine

Answer 2

@QQ_At_The_PewPew，你犯了一个错误，你正在对String＆＃34; a＆＃34;这是您的文件名，而不是您从文件中输入的文件。

import java.util.Scanner;
import java.io.*;

public class str1 {

    public static void main(String args[]) {
      try {

      String reverse = "";
      System.out.print("Enter the name of the input file: ");
      Scanner keyboard = new Scanner(System.in);
      String a = keyboard.nextLine();
      int length = a.length();
      File inFile = new File(a);
      Scanner fin = new Scanner(inFile);
      System.out.print("Enter name of the output file: ");
      String outFileName= keyboard.nextLine();
      File outFile = new File(outFileName);
      PrintWriter fout = new PrintWriter(outFile);
      while ( fin.hasNext() ) {
      String s=fin.nextLine();
      for ( int i = length - 1; i >= 0; i-- )
     reverse = reverse + s.charAt(i);

  if (s.equals(reverse))
     fout.println("Entered string is a palindrome.");
  else
     fout.println("Entered string is not a palindrome.");
      }
      fin.close();
      fout.close();
      System.out.print("Done. See '" + outFileName + "'.");
      } catch (Exception e) {
          e.printStackTrace();
      }
    }
}

简单错误（While循环）帮助在我的Java Palindrome计划中

2 个答案: