merge sort iterative 28string 29

1//Joshua Khumalo
2import java.util.Arrays;
3public class Demo{
4   public static void merge_sort(int[] my_arr){
5      if(my_arr == null){
6         return;
7      }
8      if(my_arr.length > 1){
9         int mid = my_arr.length / 2;
10         int[] left = new int[mid];
11         for(int i = 0; i < mid; i++){
12            left[i] = my_arr[i];
13         }
14         int[] right = new int[my_arr.length - mid];
15         for(int i = mid; i < my_arr.length; i++){
16            right[i - mid] = my_arr[i];
17         }
18         merge_sort(left);
19         merge_sort(right);
20         int i = 0;
21         int j = 0;
22         int k = 0;
23         while(i < left.length && j < right.length){
24            if(left[i] < right[j]){
25               my_arr[k] = left[i];
26               i++;
27            } else {
28               my_arr[k] = right[j];
29               j++;
30            }
31            k++;
32         }
33         while(i < left.length){
34            my_arr[k] = left[i];
35            i++;
36            k++;
37         }
38         while(j < right.length){
39            my_arr[k] = right[j];
40            j++;
41            k++;
42         }
43      }
44   }
45   public static void main(String[] args){
46      int my_arr[] = {56, 78, 91, 21, 34, 0, 11};
47      int i=0;
48      merge_sort(my_arr);
49      System.out.println("The array after sorting is ");
50      for(i=0; i<my_arr.length; i++)
51      System.out.print(my_arr[i]+" ");
52   }
53}