ShellSort

  public class ShellSort
   {
     private long[] data;
     private int len;
     public ShellSort(int max)
     {
       data = new long[max];
       len = 0;
     }
     public void insert(long value)
     {
       data[len] = value;
       len++;
     }
     public void display()
     {
       System.out.print("Data:");
       for (int j = 0; j < len; j++)
         System.out.print(data[j] + " ");
       System.out.println("");
     }
     public void shellSort()
     {
       int inner, outer;
       long temp;
       //find initial value of h
       int h = 1;
       while (h <= len / 3)
       h = h * 3 + 1; // (1, 4, 13, 40, 121, ...)
       while (h > 0) // decreasing h, until h=1
       {
         // h-sort the file
         for (outer = h; outer < len; outer++)
         {
           temp = data[outer];
           inner = outer;
           // one subpass (eg 0, 4, 8)
           while (inner > h - 1 && data[inner - h] >= temp)
           {
             data[inner] = data[inner - h];
             inner -= h;
           }
           data[inner] = temp;
         }
         h = (h - 1) / 3; // decrease h
       }
     }
     public static void main(String[] args)
     {
       int maxSize = 10;
       ShellSort arr = new ShellSort(maxSize);
       for (int j = 0; j < maxSize; j++)
       {
         long n = (int) (java.lang.Math.random() * 99);
         arr.insert(n);
       }
       arr.display();
       arr.shellSort();
       arr.display();
     }
   }