如何正确地将扫描程序和int传递给函数并在java中返回整数值？

Question

import java.util.Scanner; 
public class Main
{
  public static void main(String[] args)
  {
    Scanner keyboard = new Scanner(System.in);
    double score = 0, avg, sum = 0;
    int index = 0, count = 0, num = 0;

    readInput(keyboard, num);
    double Test[] = new double[num];
    System.out.print("\n");

    while(count < Test.length)
    {
      System.out.printf("Enter your test score #%d:", count + 1);
      try
      {
        score = keyboard.nextDouble();
      }

      catch(java.util.InputMismatchException e)
      {
        System.out.print("You have entered a non-numerical value, please try again\n");
        keyboard.next();
        continue;
      }
      if (score >= 0)
      {
        Test[count] = score;
        sum = sum + score;
      }
      else
      {
        System.out.print("You have entered an invalid grade, please try again\n");
        continue;
      }
      count++;
    }

    double maxValue = Test[0];
    for (int i = 1; i < Test.length; i++) 
    {
      if (Test[i] > maxValue) 
      {
        maxValue = Test[i];
      }
    }  

    double minValue = Test[0];
    for (int i = 1; i < Test.length; i++) 
    {
      if (Test[i] < minValue) 
      {
        minValue = Test[i];
        index = i;
      }
    }

    System.out.print("\nThe highest value is: " + maxValue + "\n");
    System.out.print("The lowest value is: " + minValue + "\n");

    avg = sum / Test.length;
    System.out.printf("Your grade average is: %.1f \n\n", avg);

    System.out.print("Would you like to drop the lowest grade: Y or N:");
    char choice = keyboard.next().charAt(0);

    if (choice == 'Y' || choice == 'y')
    {
      double newSum = sum - minValue;
      double newAvg = newSum / (Test.length - 1);

      System.out.print("\nYour old scores were: ");
      System.out.print(Test[0]);
      for (int i = 1; i < Test.length; i++) 
      { 
        System.out.print(", " + Test[i]);
      }

      System.out.print("\n\nYour new scores are: ");
      for (int i = 0; i < Test.length; i++) 
      { 
        if (index != 0 && i != index)
        {
          if (i >= 1)
          {
            System.out.print(", "); 
          }  
          System.out.print(Test[i]);
        } 
        else if (i != index)
        {
          if (i >= 2)
          {
            System.out.print(", "); 
          }  
          System.out.print(Test[i]); 
        }
      }

      System.out.printf("\n\nYour new average is: %.1f\n", newAvg);
    }
    else if (choice == 'N' || choice == 'n')
    {
      System.out.print("Your average has stayed the same.\n");
      return;
    }
    else
    {
      System.out.print("You have entered an invalid response. Bye.\n");
      return;
    }

  }

  public static int readInput(Scanner keyboard, int num)
  {
    System.out.print("How many scores would you like to enter:");
    try
    {
      num = keyboard.nextInt();
    }

    catch(java.util.InputMismatchException e)
    {
      System.out.print("You have entered a non-numerical value.\n");
      readInput(keyboard, num);
    }

    if (num < 0)
    {
      System.out.print("You have entered a negative value.\n");
      readInput(keyboard, num);
    }
    else if (num == 0)
    {
      System.out.print("If you have no test grades then you do not need this program.\n");
      readInput(keyboard, num);
    }
    return num;
  }
}

程序一直失败并且告诉我我错了价值。 num需要在第10行附近放入数组，但是我无法获得值返回。我需要防止用户输入错误，这就是为什么我使用输入不匹配异常，但为了将它们返回到开头，如果它们搞砸了我被告知我需要使用单独的功能。但是，这有时会导致函数的无限循环。如果有人可以帮助一种新的方式来做这件事或如何解决我目前正在做的事情那将是一个巨大的帮助。