program para
      integer pgopen
      real x(101),y(101),xp(5),yp(5)

      if( pgopen('/xwin') <= 0) stop
      xmin=0.0
      xmax=4.0
      ymin=0.0
      ymax=20.0
      call pgenv(xmin,xmax,ymin,ymax,0,0)

      dx = (xmax-xmin)/100
      do i=1,101
        x(i)=(i-1)*dx
        y(i)=x(i)*x(i)
      end do
      do i=1,5
        xp(i)=i
        yp(i)=i*i
      end do

      call pgline(101,x,y)
      call pgpt(5,xp,yp,9)
      call pgclos
      end