Texas Instruments Titanium TI-89, User Manual

Page: 773 / 977

770 Appendix A: Functions and Instructions
ClockOn
CATALOG
ClockOn
Turns the clock
ON
.
ClrDraw
CATALOG
ClrDraw
Clears the Graph screen and resets the
Smart
Graph
feature so that the next time the Graph
screen is displayed, the graph will be redrawn.
While viewing the Graph screen, you can clear all
drawn items (such as lines and points) by pressing
†
(
ReGraph
) or pressing:
@
2 ˆ
H
ˆ
and selecting 1:ClrDraw .
ClrErr
CATALOG
ClrErr
Clears the error status. It sets
errornum
to zero
and clears the internal error context variables.
The
Else
clause of the
Try...EndTry
in the program
should use
ClrErr
or
PassErr
. If the error is to be
processed or ignored, use
ClrErr
. If what to do with
the error is not known, use
PassErr
to send it to the
next error handler. If there are no more pending
Try...EndTry
error handlers, the error dialog box
will be displayed as normal.
Note: See also
PassErr
and
Try
.
Program listing:
:clearerr()
:Prgm
:PlotsOff:FnOff:ZoomStd
:For i,0,238
:
@
x
ù
i+xmin
!
xcord
: Try
: PtOn xcord,ln(xcord)
: Else
: If errornum=800 or
errornum=260 Then
: ClrErr
¦
clear the error
: Else
: PassErr
¦
pass on any other
error
: EndIf
: EndTry
:EndFor
:EndPrgm
ClrGraph
CATALOG
ClrGraph
Clears any functions or expressions that were
graphed with the
Graph
command or were created
with the
Table
command. (See
Graph
or
Table
.)
Any previously selected Y= functions will be
graphed the next time that the graph is displayed.