isalpha

isalpha

Defined in header <ctype.h>
int isalpha( int ch );

Checks if the given character is an alphabetic character, i.e. either an uppercase letter (ABCDEFGHIJKLMNOPQRSTUVWXYZ), or a lowercase letter (abcdefghijklmnopqrstuvwxyz).

In locales other than "C", an alphabetic character is a character for which isupper() or islower() returns true or any other character considered alphabetic by the locale. In any case, <