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LETTERisalnumULETTER Tests for alphanumeric characters.

Overview
#include <ctype.h>

b = isalnum(ch);

int ch;

Portability
ANSI

Description
This function checks if the passed character is a letter or a digit. For portability reasons only ASCII characters work, that is, eg. the german Umlauts (äöüß) are not accepted.

Returns
0 if the character is no letter and no digit, otherwise a value <>0.

See also