!     Last change:  DOS  24 Jul 2000    8:23 pm
!                                       *** copyright 2000 ***
! *** filename floatex.f95              *** John F. Monahan **
!                                       **********************
      program floatex
!             write out the internal representations of floating
!                point numbers -- these will be ieee standard
      implicit none
      integer i,j
      real x
      real, dimension(7) :: xl 
!
!             equivalence means use same storage for both variables
      equivalence (x,i)
!
      data xl /1.0,-1.0,.0,-15.,1.2e-38,.15e-44,3.4e+38/ 
!             compiler may be picky about .14 or .15 cutoff
!               for smallest unnormalized number
!
!             write out as floating point, internal representation
!               and lastly as fixed point
  20  format(4x,'floating pt   internal (z)   fixed point')
  21  format(4x,e12.4,4x,z8,4x,i12)
!             some compilers will only write integers in z
!
!             write the output here
      open ( UNIT=6, FILE='floatex.out' )
!
      write(6,20)
!             write seven interesting numbers
      do j = 1,7
      x = xl(j)
      write(6,21) x,i,i       ! write same number three ways
      end do  ! loop on j
!
!             the last ones as hex constants
! *** different compilers have different ways of writing ***
! **   or assigning hexadecimal constants                 **
!
      i = z'7f7fffff'         ! largest floating point number
      write(6,21) x,i,i
      i = z'7f800000'         ! infinity
      write(6,21) x,i,i
      i = z'7fffffff'         ! not-a-number -- 'NaN'
      write(6,21) x,i,i
      stop
      end program floatex
! *** end of filename floatex.f95       *********************