Indicates if a character is classed as an alphabetic character in
the program's current locale.
Format
#include <ctype.h>
int isalpha (int character);
1 – Argument
character
An object of type int. The value of character must be
representable as an unsigned char or must equal the value of the
macro EOF. If it has any other value, the behavior is undefined.
2 – Return Values
nonzero If alphabetic.
0 If not alphabetic.