java - 创建一个程序来读取文本文件并计算 5 的数量。输出关闭五分之一

Question

当我运行该程序时，一切似乎都工作正常，只是它计数为 8 个五，而实际上 txt 文件中有 9 个五。

import java.io.*;
import java.util.*;
public class FileIO2
{
    public static void main(String[] args)
    {
    Scanner kb = new Scanner(System.in);

    String filename = "Input1.txt";

    Scanner myFile = null;
    try
    {
        myFile = new Scanner(new FileInputStream(filename));
    }
    catch(Exception e)
    {
        System.out.println("File not found.");
        System.exit(0);  //close the program
    }


    int countNums = 0;
    while(myFile.hasNext())
    {
        if(myFile.hasNextInt(5))
        {
            countNums++;
        }
        myFile.next();  
    }
    System.out.println("There were " + countNums + " fives in " + filename);
    }
}

Input1.txt 文件内容:

5 9 3 2 0 5 3 0 8 5 5 55 94 3 0 65 5 5

Answer 1

我建议您对代码进行一些重构。

这个解决方案工作正常:

public class FileIO2 {
    private static final String PATH_TO_FILE = "/home/user/temp/Input1.txt";
    private static final int NUMBER_TO_FIND = 5;

    public static void main(String[] args) throws FileNotFoundException {
        int counter = 0;

        try (Scanner scanner = new Scanner(new File(PATH_TO_FILE))) {
            while (scanner.hasNextInt()) {
                int currentInt = scanner.nextInt();
                if (currentInt == NUMBER_TO_FIND) {
                    counter++;
                }
            }
        }

        System.out.println("There were " + counter + " fives in " + PATH_TO_FILE);
    }
}

代码中有问题的行是 myFile.hasNextInt(5)。