如何在不打印的情况下使用void方法？

Question

I am having problems understanding a program I need to write for class. My program works as it should, but the problem states that it wants me to not print within my methods. I am confused on how I should output my values because my methods must be void according to the problem (which doesn't return anything) and I can't print inside of them.

Here is the question:

Design and implement a java program (name it ArrayMethods), that defines 4 methods as follows:

int arrayMax (int[] array)

int arrayMin (int[] array)

void arraySquared (int[] array)

void arrayReverse (int[] array)

Test your methods by creating an array of length 5 within your main method and filling it with random numbers between 1 and 1000. Your program should then display the original array, display the smallest number in the array, display the greatest number in the array, display the revered array, and display the square of each value in the array. You main method shoudl invoke each method exactly once, with each invocation use the original array as the actual parameter. No printing within the methods. Document your code, and organize/space your outputs properly. Use escape characters and formatting objects when applicable.

So again my question is: How do I use those methods without printing anything if I can't return a value? If anyone could give me a clue on how to solve this, it would be greatly appreciated.

import java.util.Random;
import java.util.Arrays;
public class ArrayMethods
{
   public static void main (String[] args)
   {
   int[] array = new int[5];
   array[0] = (int)(Math.random() * (1000 - 1)) + 1;
   array[1] = (int)(Math.random() * (1000 - 1)) + 1;
   array[2] = (int)(Math.random() * (1000 - 1)) + 1;
   array[3] = (int)(Math.random() * (1000 - 1)) + 1;
   array[4] = (int)(Math.random() * (1000 - 1)) + 1;
     System.out.println("The values within the array are: " + Arrays.toString(array));
     System.out.println("The maximum value within the array is: " + arrayMax(array));
     System.out.println("The minimum value of the array is: " + arrayMin(array));
     System.out.print("The values within the array (squared) are: ");
     arraySquared(array);
     System.out.print("\n");
     System.out.print("The array reversed is: ");
     arrayReverse(array);
   }
   public static int arrayMax (int[] array)
   {
     int max = 0;
     for (int i = 0; i < array.length; i++)
        {
           if (array[i] > max)
              {
              max = array[i];
              }
        }
     return max;
   }

   public static int arrayMin (int[] array)
   {
     int min = 1000;
       for (int i = 0; i < array.length; i++)
              {
              if (array[i] < min)
                  {
                 min = array[i];
                  }
              }
     return min;
    }

   public static void arraySquared (int[] array)
   {
       int[] array2 = new int[5];
     for (int i = 0; i < array.length; i++)
        {
           array2[i] = array[i] * array[i];
           System.out.print(array2[i]);
              while ( i < array.length - 1)
                 {
                 System.out.print(", ");
                 break;
                 }
        }
   }

  public static void arrayReverse (int[] array)
   {
     for(int i = array.length - 1; i >= 0; i--)
        {
           System.out.print(array[i] + " ");
        }

   }
}

Answer 1

For the void functions, in C# you'd simply use an "out" or "ref" keyword. If they insist on Java, Java doesn't have an equivalent, but you can do something like that with an object.

public class PassArray
    {
        public int[] array;

        public PassArray(int[] array)
        {
            this.array = array;
        }
    }

    public static void Reverse(PassArray arrayHolder)
    {
        int[] reversed = new int[arrayHolder.array.Length];

        int j = 0;

        for (int i = arrayHolder.array.Length - 1; i >= 0; i--)
        {
            reversed[j] = arrayHolder.array[i];
            j++;
        }

        arrayHolder.array = reversed;
    }

    static void Main(string[] args)
    {
        int[] toReverse = new[] { 10, 30, 2, 1, 3, 100, 340 };

        PassArray passedObject = new PassArray(toReverse);

        Reverse(passedObject);
        // passedObject.array will now have the reversed array
    }

Obviously this could can be improved but it should at least give the right idea.