为什么我的 Java 程序跳过了“while”循环？

Question

我目前有一个问题，一个'而'循环不执行。如果输入文本文件有下一行，我将循环条件设置为true。然而，当我执行我的程序时，循环没有运行。我通过添加一个“System.out.println(text)”来确认这一点，正如我所怀疑的，没有产生任何文本。

什么问题导致循环无法执行？

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

public class BottleCapPrize
{
public static void main (String[] args) throws IOException
{
    Scanner in = new Scanner(System.in);
    PrintWriter outFile = new PrintWriter(new File("guess.txt"));
    Scanner inFile = new Scanner(new File("guess.txt"));
    Random rand = new Random();

    System.out.print("Enter number of trials: ");
    int trials = in.nextInt();

    int guess = 0;
    int totalGuess = 0;

    for (int trial = 0; trial < trials; ++trial)
    {
        guess = 0;

        int winCap = rand.nextInt(5) + 1;
        int guessCap = rand.nextInt(5) + 1;

        ++guess;
        while (guessCap != winCap)
        {
            guessCap = rand.nextInt(5) + 1;
            ++guess;
        }

        outFile.println(guess);
    }

    while (inFile.hasNextLine())
    {
        String number = inFile.nextLine();
        guess = Integer.parseInt(number);
        totalGuess += guess;

        System.out.println("This should print if while loop conditions set to true.");
    }

    double average = (double)totalGuess / trials;

    System.out.println(totalGuess + " " + guess);
    System.out.println("On average, it took " + average + " bottles to win.");
    System.out.println();

    inFile.close();
    outFile.close();

}
}

Answer 1

第一步是验证您的外部循环，for循环实际上也在运行。如果试验碰巧是0，那么您的for循环也将永远不会运行，并且您将永远不会到达而循环本身。

Answer 2

确保在使用guess.txt文件后，通过执行outFile.flush（）将内容刷新到outFile.println（猜测）文件。