program main

c*********************************************************************72
c
cc satisfy_brute_test() tests satisfy_brute().
c
c  Licensing:
c
c    This code is distributed under the MIT license.
c
c  Modified:
c
c    27 October 2022
c
c  Author:
c
c    John Burkardt
c
      implicit none

      call timestamp ( )
      write ( *, '(a)' ) ''
      write ( *, '(a)' ) 'satisfy_brute_test():'
      write ( *, '(a)' ) '  Fortran77 version'
      write ( *, '(a)' ) '  Test satisfy_brute().'

      call satisfy_brute_test01 ( )
c
c  Terminate.
c
      write ( *, '(a)' ) ''
      write ( *, '(a)' ) 'satisfy_brute_test():'
      write ( *, '(a)' ) '  Normal end of execution.'
      write ( *, '(a)' ) ''
      call timestamp ( );

      return
      end
      subroutine satisfy_brute_test01 ( )

c*********************************************************************72
c
cc satisfy_brute_test01() tests satisfy_brute().
c
c  Licensing:
c
c    This code is distributed under the MIT license.
c
c  Modified:
c
c    27 October 2022
c
c  Author:
c
c    John Burkardt
c
      implicit none

      integer formula_01
      external formula_01
      integer n

      write ( *, '(a)' ) ''
      write ( *, '(a)' ) 'satisfy_brute_test01():'
      write ( *, '(a)' ) '  satisfy_brute() seeks values of logical'
      write ( *, '(a)' ) '  variables that make a given formula true'

      n = 23

      call satisfy_brute ( n, formula_01 )

      return
      end
      function formula_01 ( bvec )

c*********************************************************************72
c
cc formula_01() returns the value of a circuit for a given input set.
c
c  Licensing:
c
c    This code is distributed under the MIT license. 
c
c  Modified:
c
c    20 March 2009
c
c  Author:
c
c    John Burkardt
c
c  Reference:
c
c    Michael Quinn,
c    Parallel Programming in C with MPI and OpenMP,
c    McGraw-Hill, 2004,
c    ISBN13: 978-0071232654,
c    LC: QA76.73.C15.Q55.
c
c  Input:
c
c    integer BVEC(N), the binary inputs.
c
c  Output:
c
c    integer formula_01: the output of the circuit.
c
      implicit none

      integer bvec(*)
      integer formula_01
      logical value

      value = ( bvec(1)  == 1 .or. bvec(2)  == 1 ) 
     &  .and. ( bvec(2)  == 0 .or. bvec(4)  == 0 ) 
     &  .and. ( bvec(3)  == 1 .or. bvec(4)  == 1 ) 
     &  .and. ( bvec(4)  == 0 .or. bvec(5)  == 0 ) 
     &  .and. ( bvec(5)  == 1 .or. bvec(6)  == 0 ) 
     &  .and. ( bvec(6)  == 1 .or. bvec(7)  == 0 ) 
     &  .and. ( bvec(6)  == 1 .or. bvec(7)  == 1 ) 
     &  .and. ( bvec(7)  == 1 .or. bvec(16) == 0 ) 
     &  .and. ( bvec(8)  == 1 .or. bvec(9)  == 0 ) 
     &  .and. ( bvec(8)  == 0 .or. bvec(14) == 0 ) 
     &  .and. ( bvec(9)  == 1 .or. bvec(10) == 1 ) 
     &  .and. ( bvec(9)  == 1 .or. bvec(10) == 0 ) 
     &  .and. ( bvec(10) == 0 .or. bvec(11) == 0 ) 
     &  .and. ( bvec(10) == 1 .or. bvec(12) == 1 ) 
     &  .and. ( bvec(11) == 1 .or. bvec(12) == 1 ) 
     &  .and. ( bvec(13) == 1 .or. bvec(14) == 1 ) 
     &  .and. ( bvec(14) == 1 .or. bvec(15) == 0 ) 
     &  .and. ( bvec(15) == 1 .or. bvec(16) == 1 ) 
     &  .and. ( bvec(15) == 1 .or. bvec(17) == 1 ) 
     &  .and. ( bvec(18) == 1 .or. bvec(2)  == 1 ) 
     &  .and. ( bvec(19) == 1 .or. bvec(1)  == 0 ) 
     &  .and. ( bvec(20) == 1 .or. bvec(2)  == 1 ) 
     &  .and. ( bvec(20) == 1 .or. bvec(19) == 0 ) 
     &  .and. ( bvec(20) == 0 .or. bvec(10) == 0 ) 
     &  .and. ( bvec(1)  == 1 .or. bvec(18) == 1 ) 
     &  .and. ( bvec(2)  == 0 .or. bvec(21) == 1 ) 
     &  .and. ( bvec(22) == 0 .or. bvec(21) == 1 ) 
     &  .and. ( bvec(23) == 0 .or. bvec(21) == 1 ) 
     &  .and. ( bvec(22) == 0 .or. bvec(21) == 0 ) 
     &  .and. ( bvec(23) == 1 .or. bvec(21) == 0 )

      if ( value ) then
        formula_01 = 1
      else
        formula_01 = 0
      end if

      return
      end
      subroutine timestamp ( )

c*********************************************************************72
c
cc timestamp() prints out the current YMDHMS date as a timestamp.
c
c  Licensing:
c
c    This code is distributed under the MIT license. 
c
c  Modified:
c
c    12 January 2007
c
c  Author:
c
c    John Burkardt
c
      implicit none

      character * ( 8 ) ampm
      integer d
      character * ( 8 ) date
      integer h
      integer m
      integer mm
      character * ( 9 ) month(12)
      integer n
      integer s
      character * ( 10 ) time
      integer y

      save month

      data month /
     &  'January  ', 'February ', 'March    ', 'April    ', 
     &  'May      ', 'June     ', 'July     ', 'August   ', 
     &  'September', 'October  ', 'November ', 'December ' /

      call date_and_time ( date, time )

      read ( date, '(i4,i2,i2)' ) y, m, d
      read ( time, '(i2,i2,i2,1x,i3)' ) h, n, s, mm

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

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

      return
      end