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我正在尝试制作一个程序，该程序为掷硬币生成“赢”或“输”，将数据输出到文件中，并读取该数据以计算平均值，但出现java.util.NoSuchElementException“错误” 。我不完全确定我为什么会得到这个..帮助将不胜感激。

import java.util.Scanner;
import java.util.Random;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.File;
public class BottleCapPrize
{
    public static void main(String [] args) throws IOException
    {            
        int random;
        int loop = 1;
        double trials = 0;
        double winCounter = 0;
        double average;
        String token = "";

        //

        Scanner in = new Scanner(System.in);
        Random rand = new Random();
        PrintWriter outFile = new PrintWriter (new File("MonteCarloMethod.txt"));

        //User Input Trials
        System.out.print("Number of trials: ");
        trials = in.nextInt();

        //For loop (random, and print to file)
        average = 0;
        for(loop = 1; loop <= trials; loop++)
        {
            random = rand.nextInt(5);
            if(random == 1)
            {
                outFile.println("Trial: " + loop + " WIN!");
            }
            outFile.println("Trial: " + loop + " LOSE");
        }

        outFile.close();

        //read output 
        File fileName = new File("MonteCarloMethod.txt");
        Scanner inFile = new Scanner(fileName);
        while (inFile.hasNextLine())
        {
            token = inFile.next();
            if (token.equalsIgnoreCase( "WIN!" ))
            {
                winCounter++;
            }

        }

        //average and print average
        average = winCounter / trials * 100;
        outFile.println("Average number of caps to win: " + average);
        System.out.println("Average number of caps to win: " + average);

        }
    }
4

2 回答 2

3

更改inFile.next()为inFile.nextLine()

此外，您将需要更改if (token.equalsIgnoreCase( "WIN!" ))为if(token.contains("WIN!"))，否则它将永远不会通过（.equals检查整行是否为“WIN！”并且只有“WIN！”，.contains检查该行是否包含“WIN！”。）

于 2014-01-10T08:06:43.710 回答
0

在您测试的阅读循环中inFile.hasNextLine()，但尝试通过inFile.next(). 但是，有下一行并不一定意味着有下一个标记。

更改hasNextLine()为hasNext()或更改next()为nextLine()（前提是所有标记都在不同的行上）。

于 2014-01-10T08:00:27.050 回答