program plot_with_auto_range
      integer pgopen
      real x(101),y(101)

      if( pgopen('/xwin') <= 0 ) stop

      dx = 10.0/100
      do i=1,101
        x(i)= -5.0 + (i-1)*dx
c       y(i)= x(i)**2
        y(i)= sin(x(i))
      end do

      xmin=x(1)
      xmax=x(1)
      ymin=y(1)
      ymax=y(1)
      do i=2,101
        if(x(i)>xmax)xmax=x(i)
        if(x(i)<xmin)xmin=x(i)
        if(y(i)>ymax)ymax=y(i)
        if(y(i)<ymin)ymin=y(i)
      end do

      call pgenv(xmin,xmax,ymin*1.2,ymax*1.2,0,0)
      call pgline(101,x,y)
      call pgclos

      end