VSI Pascal allows  you  to  supply  default  values  for  formal
  parameters.   Using default parameter values, you do not need to
  pass  actual  parameters.   Also,  you  can  specify  an  actual
  parameter  in  the  position of a formal parameter whose default
  value you want to override.

  This value can be any constant value of the type.  It must be  a
  legal  actual  parameter  for  the kind of formal parameter with
  which the default is associated.  The default-value is evaluated
  when the routine is declared.