program main
    call init
       call viewport(0.2, 0.2, 0.8, 0.8)
       call xyworld(-1.2, -1.2, 1.2, 1.2)
       call frame
       call drawline
       call fin
    stop
    end
!
    subroutine frame()
    REAL(4) :: x,y,dx,dy
    INTEGER :: i,n=10
       call  arrow( -1.1, 0.0, 1.1, 0.0, 0.02, 0.0, 1.0)
       call  arrow( 0.0, -1.1, 0.0, 1.1, 0.02, 0.0, 1.0)
       call text(1.0,-0.1,1,'x')
       call text(-0.1,1.0,1,'y')
       call text(-0.1,-0.1,1,'O')
       do i=1, n
        x=0.1*i
        if(i/5*5.eq.i)  then 
          dy=0.02
        else 
          dy=0.01
        end if
        call line( -x, -dy, -x, dy, 0.0, 1.0, 1)
        call line(  x, -dy,  x, dy, 0.0, 1.0, 1)
       end do
       do i=1, n
        y=0.1*i
        if(i/5*5.eq.i)  then 
          dx=0.02
        else 
          dx=0.01
        end if
        call line( -dx, -y, dx, -y, 0.0, 1.0, 1)
        call line( -dx,  y, dx,  y, 0.0, 1.0, 1)
       end do
    return
    end
    subroutine drawline
    REAL(4) :: x,y
    INTEGER :: i,nx=100
      x=-1.0
      y=0.0
      call linewidth(1.5)
      call plot( x, y, 3)
      do i = -nx+1,nx
        t = float(i)/float(nx)
        x = t
        y = sin(t*3.14159)
        call  plot( x, y, 2)
      end do
    return
    end