I\'m having trouble with this code. The code compiles, but whenever I run the pr

Question

I'm having trouble with this code. The code compiles, but whenever I run the program, it inevitably crashes and I receive this error message: java.lang.StackOverflowError:null.

I'm trying to recursively reverse an array in Java. My code is below. (I prompt for input in my Main and assign the input to the array.)

public class ReverseArray
{
    public static void main (String[]args)
    {
        Scanner input = new Scanner(System.in);
        int size;
       
        System.out.println();
        System.out.println ("Enter the number of elements in your array: ");
        size = input.nextInt();
        int[] myArray = new int[size];
        System.out.println();
        System.out.println ("Enter the elements of your array: ");
        for (int i = 0; i < size; i++)
        {
            myArray[i] = input.nextInt();
        }
        System.out.println();
        System.out.println ("Array: ");
        for (int i = 0; i < size; i++)
        {
            System.out.println (myArray[i] + " ");
        }
        System.out.println();
        arrayReversal(myArray, 0, myArray.length - 1);
        System.out.println ("Array reversed: ");
        printArray(myArray, 6);
       
        System.out.println();
    }
   
    static void arrayReversal(int[] array, int first, int last)
    {
        int temp;
        if (first >= last + 1)
        {
            return;
        } else
        {
        temp = array[first];
        array[first] = array[last];
        array[last] = temp;
        arrayReversal(array, first++, last--);
      }
    }

Please help.

Explanation / Answer

//Changes are in bold letters . Errors fixed in program
//Program prints the array elements in reverse order
//ReverseArray.java
import java.util.Scanner;
public class ReverseArray
{
   public static void main (String[]args)
   {
       Scanner input = new Scanner(System.in);
       int size;
       System.out.println();
       System.out.println ("Enter the number of elements in your array: ");
       //read size
       size = input.nextInt();
       int[] myArray = new int[size];
       System.out.println();
       System.out.println ("Enter the elements of your array: ");
       for (int i = 0; i < size; i++)
       {
           myArray[i] = input.nextInt();
       }
       System.out.println();
       System.out.println ("Array: ");
       for (int i = 0; i < size; i++)
       {
           System.out.println (myArray[i] + " ");
       }
       System.out.println();
      
       //calling recursive method
       arrayReversal(myArray, 0,myArray.length-1);
       System.out.println ("Array reversed: ");
       /**
       * Error Fixed:
       * Pass the argument size read by user.
       * So that method array prints the values of given size
       * */
       printArray(myArray, size);

       System.out.println();
   }

   /**The method printArray that takes an array of type integers
   * and size of the array as input arguments and prints
   * the array of given size value*/
   private static void printArray(int[] myArray, int size)
   {
      
       for (int i = 0; i < size; i++)
       {
           System.out.println(myArray[i]);
       }
      
   }

   /**Reverse the array elements calling recursive */
   static void arrayReversal(int[] array, int first, int last)
   {
       int temp;
       if (first >= last + 1)
       {
           return;
       }
       else
       {
           temp = array[first];
           array[first] = array[last];
           array[last] = temp;
           /*Error Fixed :
           * Calling method arrayReversal by adding 1 to first and subtracting
           * value one from last.
           * Do not apply incrementation or decrementation
           * on first and last variables while calling recursive methods.
           * In method recursive methods, incrementation or decrementions
           * forms infinite loops with new first and last values
           * */
           arrayReversal(array, first+1, last-1);
       }
   }
}

------------------------------------------------------------

Sample Output:

Enter the number of elements in your array:
5

Enter the elements of your array:
1
2
3
4
5

Array:
1
2
3
4
5

Array reversed:
5
4
3
2
1

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