Characters are used to express letters, numbers, signs, etc. Characters are categorized as alphanumeric and non-alphanumeric characters. Alphanumeric characters are consist of alphabet characters and numeric characters. Other than alphanumeric characters are called as non-alphanumeric characters.
Alphanumeric Characters
Alphanumeric characters consist of alphabet and numeric characters. Alphabet characters can be lower case or upper case.
Non-Alphanumeric Characters
Non-Alphanumeric characters are except alphanumeric characters. space, percent sign, underscore, pipe, colon, semicolon, etc are non-alphanumeric characters. They can be also categorized as punctuation characters, symbol characters, etc.
(blank space) ~ (tilde) ` (grave accent) ! (exclamation mark) @ (at) # (pound) $ (dollar sign) % (percent) ^ (carat) & (ampersand) * (asterisk) ( (open parenthesis) ) (close parenthesis) _ (underscore) - (hyphen) + (plus sign) = (equals) { (open brace) } (close brace) [ (open bracket) ] (close bracket) | (pipe) \ (backslash) : (colon) ; (semicolon) < (less than) , (comma) > (greater than) . (period) ? (question mark) / (forward slash)