Go forward to isspace
Go backward to isprint
Go up to Ctype
Go to the top op libc

`ispunct'--punctuation character predicate

     #include <ctype.h>
     int ispunct(int C);
`ispunct' is a macro which classifies ASCII integer values by table
lookup.  It is a predicate returning non-zero for printable punctuation
characters, and 0 for other characters.  It is defined only when
`isascii'(C) is true or C is EOF.
   You can use a compiled subroutine instead of the macro definition by
undefining the macro using ``#undef ispunct''.
`ispunct' returns non-zero if C is a printable punctuation character
(`isgraph(C) && !isalnum(C)').
`ispunct' is ANSI C.
   No supporting OS subroutines are required.