Texas Instruments TI-89

612
Appendix A: System Routines — Graphing
TI
-
89 / TI
-
92 Plus Developer Guide
Not for Distribution
Beta Version January 26, 2001
StepCk
Declaration:
void
StepCk
(BCD16 *
indep
)
Category:
Graphing
Description:
Verifies that the input min, max, and step values in the array pointed to by
indep
are valid values for the independent variable in parametric mode
(tmin, tmax, and tstep) or polar mode (
θ
min,
θ
max, and
θ
step). The
function will return to the calling routine if the values are valid, otherwise an
error is thrown.
Inputs:
indep
— Pointer to an array of BCD16 floating-point values where
indep
[0] = min,
indep
[1] = max, and
indep
[2] = step.
Outputs:
None
Assumptions:
None
Side Effects:
An error is thrown if the input values are not valid for the independent
variable in parametric mode or polar mode, such as the step value being
negative when it should have been positive for the given min and max.
Availability:
All versions of the TI-89 / TI-92 Plus.
TI
-
89 / TI
-
92 Plus
Differences:
None
See Also: CkValidDelta
Example:
if( gr_active->graph_mode == GR_PAR )
/* parametric mode - make sure viewing window variables tmin,tmax,tstep OK */
StepCk(&((gr_active->rngp)[GR_TMIN]));