shellsort.

/* shellsort: sort v[0].......v[n -1] into increasing order */
void shellsort(int v[], int n)
{
   int gap, i, j, temp;

   for(gap =n/2; gap > 0;gap /= 2)
      for(i =gap ; i < n ;i++)
         for(j =i - gap; j>= 0 && v[j] > v[j + gap]; j -=gap) {
             temp = v[j];
              v[j] =v[j + gap];
              v[j + gap] = temp;
         }
}