program read_n_plot_name_ask
      real x(100),y(100)
      character*20 my_file
      write(*,*)'Which file to plot?'
      read(*,*)my_file

      idummy=pgopen('/xwin')
      call pgenv(-10.0,10.0,-10.0,10.0,1,0)

      open(unit=12,file=my_file)

      read(12,*)np
      do i=1,np
        read(12,*)x(i),y(i)
      end do

      close(12)

      call pgline(np,x,y)
      call pgclos
      end