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嘿,所以目标是开发一个程序,该程序从文本文件中读取运动数据并将该数据的摘要打印到另一个文本文件中。输入文件由来自 txt 文件的几个记录示例输入组成,如下所示:

   1) Joe Schmoe
   76.5 20 30 25 10 75.9
   Jilly Momilly Schmill
   50.5 30 30 35 37 28 32 35 34 34 49.2
   Gail Quail
   62.3 15 17 10 3 10 63.6
   Frank Crank
   83.2 5 83.2
   John Quann
   57.9 30 32 35 32 30 57.2       

我的问题是我无法让我的代码阅读每个人我只能让它阅读第一个或让我进入无限循环或输入不匹配。这是我的代码:

`//Doubler.java
import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.InputMismatchException;
import java.io.IOException;
import java.io.BufferedWriter;
import java.io.BufferedReader;
import java.io.FileOutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.io.PrintWriter;
import java.util.Scanner;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileNotFoundException;
import java.io.EOFException;
import java.io.IOException;

public class ExerciseSummary
{
    private Scanner inputStream = null;
    private PrintWriter outputStream = null;
    private int next = 0;
    private int sum = 0;
    private int count = 0;
    private double avg = 0;
    private double firstWeight = 0;
    private double lastWeight = 0;
    private String line;

    public static void main(String[] args)
        {
        ExerciseSummary summary = new ExerciseSummary();
        summary.connectToInputFile();
        summary.connectToOutputFile();
        summary.summaryData();
        summary.closeFiles();
        System.out.println("\nAll numbers from the input file have been");
        System.out.println("summarized and copied to the output file.");
    }

    public void connectToInputFile()
    {
        String inputFileName = getFileName("\nEnter name of input file: ");
        try
        {
            inputStream =
                new Scanner(new File(inputFileName));
        }
        catch(FileNotFoundException e)
        {
            System.out.println("File " + inputFileName + " not found.");
            System.exit(0);
        }
        catch(IOException e)
        {
            System.out.println("Error opening input file " + inputFileName);
            System.exit(0);
        }
    }

    private String getFileName(String prompt)
    {
        String fileName = null;
        System.out.print(prompt);
        Scanner keyboard = new Scanner(System.in);
        fileName = keyboard.next();
        return fileName; 
    }

    public void connectToOutputFile()
    {
        String outputFileName = getFileName("Enter name of output file: ");
        try
        {
            //outputStream = new PrintWriter(outFile);
            outputStream =
                new PrintWriter(outputFileName);
        }
        catch(IOException e)
        {
            System.out.println("Error opening output file " + outputFileName);
            //System.out.println(e.getMessage());
            System.exit(0);
        }
    }

    public void summaryData()
    {
        try 
        {
            while (inputStream.hasNext());
            {
                line = inputStream.nextLine();
                firstWeight = inputStream.nextDouble();
                while (inputStream.hasNextInt()) 
                {
                            sum += inputStream.nextInt();
                    count ++;
                    avg = (sum/count);
                    }
                lastWeight = inputStream.nextDouble();
                        outputStream.println(line + " " + firstWeight + " " + sum + " " +  count + " " +  lastWeight + " " + avg + " " + (lastWeight-firstWeight));
            }
        }
        catch (InputMismatchException e) 
        {
            System.out.print(e);
            System.exit(0);
        }
    }

    public void closeFiles()
    {
            inputStream.close();
            outputStream.close();
    }
}       

输出记录是输入记录的摘要。它由四个 TAB 分隔值组成:该参与者的数据天数、锻炼的总分钟数、每天平均锻炼的分钟数和总体重减轻(如果参与者体重增加,则为负数) . 该名称已被读入,但没有再次打印出来(我们正在匿名化数据)。对于上面的记录,受试者的名字是 Joe Schmoe,他的起始体重是 76.5 公斤。Joe 锻炼了四天(起始体重和最终体重之间有四个 int 值),总共 85 分钟(20 + 30 + 25 + 10 = 85)。他的最终体重是75.9公斤。输出记录为:4 85 21.25 0.5999999999999943

我已经绞尽脑汁两周了,任何帮助将不胜感激,谢谢

4

1 回答 1

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无限循环:

while (inputStream.hasNext());
        {
            line = inputStream.nextLine();
            firstWeight = inputStream.nextDouble();
            while (inputStream.hasNextInt()) 
            {
                        sum += inputStream.nextInt();
                count ++;
                avg = (sum/count);
                }
            lastWeight = inputStream.nextDouble();
                    outputStream.println(line + " " + firstWeight + " " + sum + " " + count + " " +  lastWeight + " " + avg + " " + (lastWeight-firstWeight));
        }

“;” “while (inputStream.hasNext())”之后是一个空表达式,所以java简单地执行“;” 而 inputStream.hasNext() 并且不使用文件

下一个问题,InputMissmatchException:你需要扫描仪这一行:

inputStream =
            new Scanner(new File("C:\\Test\\readTest.txt"));
inputStream.useLocale(Locale.ENGLISH);//this will help to interpret "." as decimal character

最后一个问题,您需要在 while 末尾使用这 2 行来使用“换行符”字符:

lastWeight = inputStream.nextDouble();
                    outputStream.println(line + " " + firstWeight + " " + sum + " " +  count + " " +  lastWeight + " " + avg + " " + (lastWeight-firstWeight));
if(inputStream.hasNext())
    inputStream.next(); // or even inputStream.nextLine();

现在我得到第一人称:Joe Schmoe 76.5 85 4 75.9 21.0 -0.5999999999999943 这是正确的结果吗?

于 2014-03-06T19:35:00.023 回答