NAME

isalpha, isupper, islower, isdigit, isalnum, isspace, ispunct, isprint, iscntrl, isascii − character classification

SYNOPSIS

#include <ctype.h>

isalpha(c)

. . . 

DESCRIPTION

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(3)).

isalpha c is a letter

isupper c is an upper case letter

islower c is a lower case letter

isdigit c is a digit

isalnum c is an alphanumeric character

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

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

isprint c is a printing character, code 040(8) (space) through 0176 (tilde)

iscntrl c is a delete character (0177) or ordinary control character (less than 040). 

isascii c is an ASCII character, code less than 0200

SEE ALSO

ascii(7)

7th Edition