program para
      real x(101),y(101),xp(5),yp(5)
      if(pgopen('/xwin')<=0)stop
      call pgenv(0.0,5.0,0.0,20.0,0,0)
      call pglab('x','y','y(x)=x\u2')
      dx=(5.0-0.0)/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