program parabola

      implicit none
      real x, delta_x
      integer i

      delta_x = ((1.0) - (-1.0))/200

      open(unit=20,file='parabola.dat')

      x = -1.0
      write(20,*) x, x**2

c     do i=1,200
c       x = (-1.0) + i*delta_x
c       write(20,*) x, x**2
c     end do

      do i=1,200
        x = x + delta_x
        write(20,*) x, x**2
      end do

      close(20)

      end