program main

c*********************************************************************72
c
cc CIRCLE_GRID_TEST tests CIRCLE_GRID.
c
c  Licensing:
c
c    This code is distributed under the GNU LGPL license.
c
c  Modified:
c
c    09 November 2011
c
c  Author:
c
c    John Burkardt
c
      implicit none

      call timestamp ( )
      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 'CIRCLE_GRID_TEST:'
      write ( *, '(a)' ) '  FORTRAN77 version'
      write ( *, '(a)' ) '  Test the CIRCLE_GRID library.'

      call circle_grid_test01 ( )
c
c  Terminate.
c
      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 'CIRCLE_GRID_TEST:'
      write ( *, '(a)' ) '  Normal end of execution.'
      write ( *, '(a)' ) ' '
      call timestamp ( )

      return
      end
      subroutine circle_grid_test01 ( )

c*********************************************************************72
c
cc CIRCLE_GRID_TEST01 tests CIRCLE_GRID.
c
c  Licensing:
c
c    This code is distributed under the GNU LGPL license.
c
c  Modified:
c
c    09 November 2011
c
c  Author:
c
c    John Burkardt
c
      implicit none

      double precision c(2)
      double precision cg(2,4000)
      character * ( 80 ) filename
      integer n
      integer ng
      double precision r

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 'TEST01:'
      write ( *, '(a)' ) '  CIRCLE_GRID can define a grid of points'
      write ( *, '(a)' ) 
     &  '  with N+1 points on a horizontal or vertical radius,'
      write ( *, '(a)' ) '  based on any circle.'

      n = 20
      r = 2.0D+00
      c(1) = 1.0D+00
      c(2) = 5.0D+00

      write ( *, '(a)' ) ' '
      write ( *, '(a,i8)' ) '  We use N = ', n
      write ( *, '(a,g14.6)' ) '  Radius R = ', r
      write ( *, '(a,g14.6,a,g14.6,a)' ) 
     &  '  Center C = (', c(1), ',', c(2), ')'

      call circle_grid_count ( n, r, c, ng )

      write ( *, '(a)' ) ' '
      write ( *, '(a,i8)' ) '  Number of grid points will be ', ng

      call circle_grid ( n, r, c, ng, cg )

      call r82vec_print_part ( ng, cg, 20, 
     &  '  Part of the grid point array:' )

      filename = 'circle_grid_test01.xy'

      call r8mat_write ( filename, 2, ng, cg )

      write ( *, '(a)' ) ' '
      write ( *, '(a)' ) 
     &  '  Data written to the file "' // trim ( filename ) // '".'


      return
      end