It is informative when learning a new language to have side-by-side
  comparisons with other languages. Below is the output of the same program
  in Fortran, Ada and C. Then, on the following pages is the source code.
  Ada and C have specifications while Fortran does not.
  The subroutine, procedure, function is given for a Shelli sort.
  The main program, procedure, function is given to test the Shelli sort.

  MMM       1.000000 
  NNN       2.000000 
  AAA       3.000000 
  CCC       4.000000 
  BBB       5.000000 
  ZZZ       6.000000 
  XXX       7.000000 
  PPP       8.000000 
  QQQ       9.000000 
  DDD       10.000000 
  EEE       11.000000 
  FFF       12.000000 
  GGG       13.000000 
  HHH       14.000000 
  III       15.000000 
  JJJ       16.000000 
  KKK       17.000000 
  LLL       18.000000 
  OOO       19.000000 
  RRR       20.000000 
  Sorted by name 
  AAA       3.000000 
  BBB       5.000000 
  CCC       4.000000 
  DDD       10.000000 
  EEE       11.000000 
  FFF       12.000000 
  GGG       13.000000 
  HHH       14.000000 
  III       15.000000 
  JJJ       16.000000 
  KKK       17.000000 
  LLL       18.000000 
  MMM       1.000000 
  NNN       2.000000 
  OOO       19.000000 
  PPP       8.000000 
  QQQ       9.000000 
  RRR       20.000000 
  XXX       7.000000 
  ZZZ       6.000000