Iterator for 2-D Array in a clockwise inward sprial

Objective:

Implement an iterator for a 2-dimensional array data structure that moves in a clockwise inward spiral

Example:

Input A[4,4] array

01 02 03 04

05 06 07 08

09 10 11 12

13 14 15 16

The above 2-D array would iterate the following way

01 02 03 04 08 12 16 15 14 13 09 05 06 07 11 10

Solution: The problem can be solved in many different ways. I have solved this problem in Java Programming language using recursive way.

public class InwardSprial {

  public void top_bottom(T[][] a, int x1, int y1, int x2, int y2) {

      for (int i = y1; i < y2; i++) {
          display(a[x1][i]);
      }
      x1 = x1 + 1;
      if(!hasNext((x2-x1),(y2-y1))) {
          return;
      }
   
      for (int j = x1; j < x2; j++) {
          display(a[j][y2 - 1]);
      }
      y2 = y2 - 1;
      if(!hasNext((x2-x1),(y2-y1))) {
          return;
      }
      bottom_top(a, x1, y1, x2, y2);
  }

  private void display(T value) {
      System.out.print(value + "\t");
  }

  private boolean hasNext(int x, int y) {
      if (x==0 || y==0) {
          return false;
      }
      return true;
  }

  private void bottom_top(T[][] a, int x1, int y1, int x2, int y2) {
      int i = 0, j = 0;
   
      for (i = y2 - 1; i >= y1; i--) {
          display(a[x2 - 1][i]);
      }
      x2 = x2 -1;
      if(!hasNext((x2-x1),(y2-y1))) {
          return;
      }

      for (j = x2 - 1; j >= x1; j--) {
          display(a[j][y1]);
      }
      y1 = y1 +1;
      if(!hasNext((x2-x1),(y2-y1))) {
          return;
      }
   
      top_bottom(a, x1, y1, x2, y2);
  }

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

      int x=5,y=4;
      Integer[][] a = new Integer[x][y];
      int num =0;
      for (int i=0; i is = new InwardSprial();
      is.top_bottom(a, 0, 0, x, y);
  }

}