Char Type.

These routines test a single character for a particular condition:

Routine Use
isalnum Alphanumeric
isalpha Alphabetic
isblank Printable, with no symbol
iscntrl Control
isdigit Decimal digit
isgraph Printable non-space
islower Lower case
isprint Printable
ispunct Punctuation
isspace Whitespace
isupper Upper case
isxdigit Hexadecimal digit