program main

!*****************************************************************************80
!
!! byname_test() tests byname().
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    10 May 2021
!
!  Author:
!
!    John Burkardt
!
  implicit none

  integer, parameter :: rk = kind ( 1.0D+00 )

  real ( kind = rk ) alpha
  real ( kind = rk ) beta
  real ( kind = rk ) gamma
  real ( kind = rk ) value

  interface
    subroutine byname ( action, name, value_in, value_out )
      integer, parameter :: rk = kind ( 1.0D+00 )
      character ( len = * ), optional :: action
      character ( len = * ), optional :: name
      real ( kind = rk ), optional :: value_in
      real ( kind = rk ), optional :: value_out
    end subroutine
  end interface

  call timestamp ( )
  write ( *, '(a)' ) ''
  write ( *, '(a)' ) 'byname_test():'
  write ( *, '(a)' ) '  FORTRAN90 version'
  write ( *, '(a)' ) '  Test byname(), with the interface:'
  write ( *, '(a)' ) '    call byname(action,name,value_in,value_out)'
  write ( *, '(a)' ) ''
  write ( *, '(a)' ) '    byname ( "print", "*" )'
  call byname ( action = "print", name = "*" )
  write ( *, '(a)' ) '    alpha = byname ( "set", "alpha", 1.0 )'
  call byname ( action = "set", name = "alpha", value_in = 1.0D+00, value_out = alpha )
  write ( *, '(a)' ) '    beta = byname ( "set", "beta", 99 )'
  call byname ( action = "set", name = "beta", value_in = 99.0D+00, value_out = beta )
  write ( *, '(a)' ) '    byname ( "set", "gamma", alpha + beta )'
  value = alpha + beta
  call byname ( action = "set", name = "gamma", value_in = value, value_out = gamma )
  write ( *, '(a)' ) '    byname ( "print", "*" )'
  call byname ( action = "print", name = "*" )
  write ( *, '(a)' ) '    gamma = byname ( "get", "gamma" )'
  call byname ( action = "get", name = "gamma", value_out = gamma )
  write ( *, '(a)' ) '    byname ( "set", "gamma", 2.0*gamma )'
  value = 2.0 * gamma
  call byname ( action = "set", name = "gamma", value_in = value )
  write ( *, '(a)' ) '    byname ( "print", "gamma" )'
  call byname ( action = "print", name = "gamma" )
  write ( *, '(a)' ) '    byname ( "print", "*" )'
  call byname ( action = "print", name = "*" )
  write ( *, '(a)' ) '    byname ( "reset" )'
  call byname ( action = "reset" )
  write ( *, '(a)' ) '    byname ( "print", "*" )'
  call byname ( action = "print", name = "*" )
!
!  Terminate.
!
  write ( *, '(a)' ) ''
  write ( *, '(a)' ) 'byname_test():'
  write ( *, '(a)' ) '  Normal end of execution.'
  write ( *, '(a)' ) ''
  call timestamp ( )

  stop ( 0 )
end
subroutine timestamp ( )

!*****************************************************************************80
!
!! timestamp() prints the current YMDHMS date as a time stamp.
!
!  Example:
!
!    31 May 2001   9:45:54.872 AM
!
!  Licensing:
!
!    This code is distributed under the MIT license.
!
!  Modified:
!
!    18 May 2013
!
!  Author:
!
!    John Burkardt
!
  implicit none

  integer, parameter :: rk = kind ( 1.0D+00 )

  character ( len = 8 ) ampm
  integer d
  integer h
  integer m
  integer mm
  character ( len = 9 ), parameter, dimension(12) :: month = (/ &
    'January  ', 'February ', 'March    ', 'April    ', &
    'May      ', 'June     ', 'July     ', 'August   ', &
    'September', 'October  ', 'November ', 'December ' /)
  integer n
  integer s
  integer values(8)
  integer y

  call date_and_time ( values = values )

  y = values(1)
  m = values(2)
  d = values(3)
  h = values(5)
  n = values(6)
  s = values(7)
  mm = values(8)

  if ( h < 12 ) then
    ampm = 'AM'
  else if ( h == 12 ) then
    if ( n == 0 .and. s == 0 ) then
      ampm = 'Noon'
    else
      ampm = 'PM'
    end if
  else
    h = h - 12
    if ( h < 12 ) then
      ampm = 'PM'
    else if ( h == 12 ) then
      if ( n == 0 .and. s == 0 ) then
        ampm = 'Midnight'
      else
        ampm = 'AM'
      end if
    end if
  end if

  write ( *, '(i2.2,1x,a,1x,i4,2x,i2,a1,i2.2,a1,i2.2,a1,i3.3,1x,a)' ) &
    d, trim ( month(m) ), y, h, ':', n, ':', s, '.', mm, trim ( ampm )

  return
end