Character Classification / Conversion; Isalnum - Texas Instruments TI-89 Developer's Manual

Appendix C: Macros — Character Classification / Conversion

isalnum

Declaration: BYTE isalnum (BYTE c )
Category(ies):

Character Classification / Conversion

Description: Return non-zero (true) if the given character is alpha-numeric.
Inputs: c
Outputs: Non-zero if c is alpha-numeric, zero otherwise.
Assumptions: Access_AMS_Global_Variables is defined.
Side Effects: None
Availability: AMS 2.00 or above.
TI-89 / TI-92 Plus
Differences: None
See Also: isalpha, isdigit
Example: This example function returns 0 . . . 8 if passed the digits '1' . . . '9' and
9 . . . 34 if passed 'A' . . . 'Z' or 'a' . . . 'z'; all other characters return -1.
Note that the isascii function prevents any of the international alphabetical
characters from being used.
SINT SubChar2I( SINT c )
{ Access_AMS_Global_Variables;
if (isascii(c)) {
c = toupper(c);
if (isalnum(c) && c != '0')
return( ((c < 'A') ? (c - '1') : (c - ('0' + 'A'-'9'))) );
}
return -1;
}
TI-89 / TI-92 Plus Developer Guide
— Character to test.
Not for Distribution
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Beta Version January 26, 2001