An email address identifies an email box to which messages are delivered. Every email address consists of 3 elements: local-part, @ symbol (pronounced as at), and domain name. The local-part is placed before the @ symbol, and the domain name is placed after the @ symbol. For example, in the email johndoe@company.com, johndoe is the local-part, and company.com is the domain. Emails are invalid without these elements. The local-part or username contains:

a. uppercase and lowercase Latin letters (A-Z, a-z);

b. numeric values (from 0 to 9);

c. special characters, such as # ! % $ & + * / = ? ^ _`. { | } ~

i. The period character (.) is valid for the local-part unless it is placed at the beginning or end of an email address. There also cant be two or more periods in a row

A domain name consists of one or more parts separated by a dot and can contain:

a. uppercase and lowercase Latin letters (A-Z, a-z);

b. numeric values (from 0 to 9);

c. a hyphen (-), on condition that it is not placed at the beginning or end of the domain

1. (9 points) Create a regular expression, DFA, and Regular Grammar for the local-part of the email address.

2. (9 points) Create a regular expression, DFA, and Regular Grammar for the domain of the email address.

3. (2 points) Create a NFA for an email address.