Important Notice

The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.

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  Include:   <ctype.h>
 
  Syntax:    int isalnum( int c );   (alphanumeric character)
             int isalpha( int c );   (alphabetic character)
             int isascii( int c );   (ASCII character)
             int iscntrl( int c );   (control character)
             int isdigit( int c );   (decimal digit)
             int isgraph( int c );   (printable character, not space)
             int islower( int c );   (lowercase letter)
             int isprint( int c );   (printable character)
             int ispunct( int c );   (punctuation character)
             int isspace( int c );   (white-space character
             int isupper( int c );   (uppercase letter)
             int isxdigit( int c );  (hexadecimal digit)
 
  Returns:   a nonzero value if the condition is true, or 0 if it
             is not.
 
  See also:  toascii, tolower, toupper
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