c===========================================================
c     Test program for subroutine 'dvto'.
c
c     Program expects two arguments, the name of a file 
c     for output ('-' for stdout) and the length of the 
c     test vector to be written.
c===========================================================
      program         tdvto

      implicit        none

c-----------------------------------------------------------
c     The integer function 'i4arg' is defined in the 
c     'p410f' library.  It takes two arguments, the first 
c     is an integer specifying which program argument is 
c     to be parsed as an integer, and the second is a 
c     default value which will be returned if the argument
c     was not supplied or could not be converted to an 
c     integer.
c-----------------------------------------------------------
      integer         iargc,      i4arg

      integer         maxn
      parameter     ( maxn = 100 000 )
      real*8          v(maxn)
      integer         n

      integer         i
      character*256   fname

c-----------------------------------------------------------
c     Unless exactly two arguments are supplied, print usage
c     message and exit.
c
c     Note the use of the "logical-if" statement (no then)
c-----------------------------------------------------------
      if( iargc() .ne. 2 ) go to 900

      call getarg(1,fname)
      n = i4arg(2,-1)
      if( n .eq. -1 ) go to 900
c-----------------------------------------------------------
c     Limit the value of n
c-----------------------------------------------------------
      n = min(n,maxn)
c-----------------------------------------------------------
c     Define test vector
c-----------------------------------------------------------
      do i = 1 , n
         v(i) = i 
      end do

c-----------------------------------------------------------
c     Call the routine ..
c-----------------------------------------------------------
      call dvto(fname,v,n)

c-----------------------------------------------------------
c     Normal exit
c-----------------------------------------------------------
      stop

c-----------------------------------------------------------
c     Usage exit
c-----------------------------------------------------------
 900  continue
         write(0,*) 'usage: tdvto <file name> <n>'
         write(0,*)
         write(0,*) '       Use ''tdvto -'' to write ',
     &              'to standard output'

      stop

      end