Problem Statement

Special characters are symbols (single characters or sequences of characters) that have a "special" built-in meaning in the language and typically cannot be used in identifiers. Escape sequences are methods that the language uses to remove the special meaning from the symbol, enabling it to be used as a normal character, or sequence of characters when this can be done.

List the special characters and show escape sequences in the language.

Let's start with the solution:

^[a-zA-Z_][a-zA-Z_0-9]*$