[英]Why is my Java program skipping a 'while' loop?
我目前遇到“ while”循环未执行的问题。 如果输入文本文件具有下一行,则将循环条件设置为true。 但是,当我执行程序时,循环未运行。 我通过添加'System.out.println(text)'确认了这一点,并且我怀疑没有文本产生。
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();
}
}
在使用outFile.println(guess)
之后,请确保通过执行outFile.flush()
将内容刷新到guess.txt
文件。
第一步是验证您的外部循环, for循环是否也正在运行。 如果试验恰好为0,则您的for循环将永远不会运行,并且您也永远不会到达while循环本身。
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