Java Program for ShellSort

// Java implementation of ShellSort 
class ShellSort { 
 /* An utility function to print array of size n*/
 static void printArray(int arr[]) 
 { 
  int n = arr.length; 
  for (int i = 0; i < n; ++i) 
   System.out.print(arr[i] + " "); 
  System.out.println(); 
 } 

 /* function to sort arr using shellSort */
 int sort(int arr[]) 
 { 
  int n = arr.length; 

  // Start with a big gap, then reduce the gap 
  for (int gap = n / 2; gap > 0; gap /= 2) { 
   // Do a gapped insertion sort for this gap size. 
   // The first gap elements a[0..gap-1] are already 
   // in gapped order keep adding one more element 
   // until the entire array is gap sorted 
   for (int i = gap; i < n; i += 1) { 
    // add a[i] to the elements that have been gap 
    // sorted save a[i] in temp and make a hole at 
    // position i 
    int temp = arr[i]; 

    // shift earlier gap-sorted elements up until 
    // the correct location for a[i] is found 
    int j; 
    for (j = i; j >= gap && arr[j - gap] > temp; j -= gap) 
     arr[j] = arr[j - gap]; 

    // put temp (the original a[i]) in its correct 
    // location 
    arr[j] = temp; 
   } 
  } 
  return 0; 
 } 

 // Driver method 
 public static void main(String args[]) 
 { 
  int arr[] = { 12, 34, 54, 2, 3 }; 
  System.out.println("Array before sorting"); 
  printArray(arr); 

  ShellSort ob = new ShellSort(); 
  ob.sort(arr); 

  System.out.println("Array after sorting"); 
  printArray(arr); 
 } 
} 
/*This code is contributed by Rajat Mishra */