Question

After reading in a line from a file and splitting that line into tokens, I need to check if the token only contains alphabetic characters [a-zA-Z]. Is there some sort of function in the C Standard Library to check this? I could use regex.h to check this but I think this is overblown.

Sure, I could write a function that loops over the token and checks every char, but I don’t want to reinvent the wheel.

P.S.: Using a third party library is not an option.

Answer 1

Certainly:

#include <ctype.h>

int isalpha(int ch) // is alphabetic?
int isalnum(int ch) // is alphanumeric?