Texas Instruments TI-89 Titanium User Manual page 623

Debugging Techniques
Run-time error messages can locate syntax errors but not errors in program logic. The
following techniques may be useful.
• During testing, do not use local variables so that you can check the variable values
after the program stops. When the program is debugged, declare the applicable
variables as local.
• Within a program, temporarily insert
values of critical variables.
- and
Disp Pause
change the function into a program, change
. Use
EndPrgm
and change the program back into a function.
Pause
• To confirm that a loop is executed the correct number of times, display the counter
variable or the values in the conditional test.
• To confirm that a subroutine is executed, display messages such as
and
subroutine
Error-Handling Commands
Command Description
Try...EndTry Defines a program block that lets the program execute a
command and, if necessary, recover from an error
generated by that command.
ClrErr Clears the error status and sets the error number in system
variable Errornum to zero.
PassErr Passes an error to the next level of the Try...EndTry block.
Programming
cannot be used in a user-defined function. To temporarily
and
Disp Pause
Exiting subroutine
and commands to display the
Disp Pause
Func
to debug the program. Then remove
at the beginning and end of the subroutine.
and to
EndFunc Prgm
Entering
and
and
Disp
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