- isalpha
-
c
is a letter
- isupper
-
c
is an upper case letter
- islower
-
c
is a lower case letter
- isdigit
-
c
is a digit [0-9]
- isxdigit
-
c
is a hexadecimal digit [0-9], [A-F] or [a-f]
- isalnum
-
c
is an alphanumeric
- isspace
-
c
is a space, tab, carraige return, new-line, vertical tab, or form-feed
- ispunct
-
c
is a punctuation character (neither control nor alphanumeric)
- isprint
-
c
is a printing character, code 040 (space) through 0176 (tilde)
- isgraph
-
c
is a printing character, like isprint except false for space
- iscntrl
-
c
is a delete character (0177) or ordinary control character (less
than 040)
- isascii
-
c
is an ASCII character, code less than 0200