@(#)ctype.3 6.1 (Berkeley) 05/15/85

.AT 3 isalpha, isupper, islower, isdigit, isxdigit, isalnum, isspace, ispunct, isprint, iscntrl, isascii - character classification macros #include <ctype.h>

isalpha(c)

. . .

These macros classify ASCII-coded integer values by table lookup. Each is a predicate returning nonzero for true, zero for false. Isascii is defined on all integer values; the rest are defined only where isascii is true and on the single non-ASCII value EOF (see stdio (3S)).

15n isalpha c is a letter

isupper c is an upper case letter

islower c is a lower case letter

isdigit c is a digit

isxdigit c is a hex digit

isalnum c is an alphanumeric character

isspace c is a space, tab, carriage return, newline, vertical tab, or formfeed

ispunct c is a punctuation character (neither control nor alphanumeric)

isprint c is a printing character, code 041(8) (exclamation point) through 0176 (tilde)

iscntrl c is a delete character (0177) or ordinary control character (less than 040 and not isspace(c)).

isascii c is an ASCII character, code less than 0200

ascii(7)