For 循环打印到文件永远加载并且文件空白，即使关闭？

Question

我正在尝试编写代码，通过从 10 中选择一个随机数来模拟 1000 多次试验的蒙特卡洛方法，直到数字为 10，然后每次都会增加（观察到的松鼠数量）的计数器，直到随机数数字是 10；然后这个计数器将被打印到一个文件中。然而，这是通过在 in 中嵌套循环的 For 循环完成的，但程序似乎在此 For 循环中永远加载一次，并且即使使用了 close() 文件也保持空白。import java.io.IOException;import java.io.PrintWriter;import java.io.File;import java.util.Scanner;import java.util.Random;public class AnimalPopulation{    public static void main(String[] args) throws IOException    {    //declare and initialize variables    Random randsquirrel = new Random();    Scanner in = new Scanner(System.in);    PrintWriter outFile = new PrintWriter(new File ("squirreldata.txt"));    // User input    System.out.println("Welcome to the Fox Squirrel Simulator");    System.out.println("\n");    System.out.println("How many trials should be simulated?");    System.out.println("Enter a value greater than 1000:");    int trialcounter = in.nextInt();    // Input does not match requirements    while (trialcounter <= 1000)    {        System.out.print("\n\n  Please try again. Enter a number greater than 1000.");        System.out.println();        System.out.println("How many trials should be simulated?");        System.out.println("Enter a value greater than 1000:");        trialcounter = in.nextInt();    }    System.out.println("\nsimulating trials now... one moment please ...");    // Experiment with ratio of 1/10 fox squirrels     int randomsquirrel = 0;    int totalsquirrels = 0;    for (int i = 1; i <= trialcounter; i++)    {        randomsquirrel = randsquirrel.nextInt(10)+1;            while (randomsquirrel != 10)            {                totalsquirrels++;            }                if (randomsquirrel == 10);                {                    totalsquirrels++;                }        outFile.println(totalsquirrels);    }

Answer 1

你能告诉我这里有什么问题吗？

    randomsquirrel = randsquirrel.nextInt()+1;

    while (randomsquirrel != 10)

    {

        totalsquirrels++;

    }

While 循环由 3 个部分组成：while 关键字、(condition) 和 {lines to run}

while (condition) {

    //lines to run.

}

首先检查条件是否轮到它将执行所有要运行的行。完成所有行后，它会再次检查条件。如果条件仍然为真，它将再次运行所有行。它将永远运行这些线路，直到条件变为假或遇到中断为止。

Answer 2

您使用不正确的 while 因为您永远不会更改 while 循环中的值，这会导致无限循环。正确的方法：

public static void main(String[] args) throws IOException

{

    SecureRandom randsquirrel = new SecureRandom(); // it is better

    // rest of your code

    int randomsquirrel = 0;

    int totalsquirrels = 0;

    for (int i = 1; i <= trialcounter; i++)

    {

        randomsquirrel = randsquirrel.nextInt(10)+1;

        while (randomsquirrel != 10)

        {                               

            randomsquirrel = randsquirrel.nextInt(10) + 1:

            totalsquirrels++;

            if (randomsquirrel == 10);

                break;

        }                      

    }

    // rest of your code

}