Full prototype:
int isalnum(int);
Purpose and Notes:
Tests whether a character passed into it is alphanumerical and returns a C-style true or false.
Returns:
int- C-style true or false based on whether the character passed in was a alphanumerical or not.
Argument 1:
int- A character type including the EOF character (hence int instead of char) to be evaluated for whether it is a alphanumerical character or not.