為什么我的Java程序跳過“ while”循環？

Question

我目前遇到“ while”循環未執行的問題。 如果輸入文本文件具有下一行，則將循環條件設置為true。 但是，當我執行程序時，循環未運行。 我通過添加'System.out.println（text）'確認了這一點，並且我懷疑沒有文本產生。

什么問題導致循環無法執行？

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

在使用outFile.println(guess)之后，請確保通過執行outFile.flush()將內容刷新到guess.txt文件。

Answer 2

第一步是驗證您的外部循環， for循環是否也正在運行。 如果試驗恰好為0，則您的for循環將永遠不會運行，並且您也永遠不會到達while循環本身。