The document describes an email validation project created by five students. The project uses regular expressions and a finite state machine to check if an entered email address matches the standard syntax of a valid email address as defined in RFC 5322. It validates the local part, domain part, and that they are separated by an @ symbol. The code uses a regular expression pattern and Regex.Match method to test entered emails.

1. Hashim Naseer Lokasher
Muazzam Ali Sundhu
Haseeb Mehmood
Gohar Naseer
Muhammad Qasim Ali
11014119-129
11014119-099
11014119-089
11014119-087
11014119-128
THEORY OF AUTOMATA
PROJECT TITLE: EMAIL VALIDATOR

2. Introduction
Email Validator

3. Email Validator
What does Validation means?

4. Validation
Validation is the process of checking data against a
standard or requirement.
The term is commonly used when:
Checking the information entered by a person when
storing data, sending information or using an online
service (FORM VALIDATION).

5. Email Validation
So,
Email Validation means to validate
and check an email address.

6. Our Project
Is a email validator, which
Validates an Email Address
Check the grammar and syntax
Can be used in Data Entry forms and
Applications

7. Screenshot
C# Programming Language is
used for the development of this
application.
WinForm and Regular Expressions
class is also used

8. Program Working
Email Validator

9. So,
What is a
Valid Email Address?

10. Valid Email Address
There's only one real answer to this:
A valid email address is one that you can send emails to
Contemporary email addresses consist of a "local part"
separated from a "domain part" (a fully-qualified domain
name) by an at-sign ("@").
Mymail@mycompany.com is a valid Email Address

11. Regular Expressions
 If you only want to check if an address is grammatically
correct then you could use a regular expression
 Using a regular expression that recognizes email addresses
could be useful in various situations:
For example
to scan for email addresses in a document,
to validate user input,
or as an integrity constraint on a data repository.

12. Regular Expressions
Regular expressions are a very cool feature for
pattern recognition in strings.
Mathematically speaking regular expressions are
parsed through a "finite state machine".
As the name implies, such a machine has only a
finite number of states, and it has no external
memory attached.

13. Parsing
Parsing or syntactic analysis is the process of
analysing a string of symbols, either in natural
language or in computer languages,
according to the rules of a formal grammar.

14. Regular Expression Processor
A regular expression processor processes a regular
expression statement expressed in terms of a
grammar in a given formal language, and with
that examines the target text string, parsing it to
identify substrings that are members of its
language, the regular expressions.

15. "^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+.[a-zA-Z0-9-.]+$"

16. Regular Expression for Email Validation
Myname@mycompany.com can be validated as
"^[a-zA-Z0-9_.+-]+@[a-zA-Z0-9-]+.[a-zA-Z0-9-.]+$"
Myname
@
mycompany .
com
We compared the given email address with the upper RegEx to validate it is synthetically
correct or not.

17. Regular Expressions
Any validation problems that involve
recursion, option, limitation is easier
to solve with regular expressions than
using other ways (like if-else if-else,
while condition)

18. Regular Expressions
Regular Expressions can be used to
Test if a string matches some pattern.
Scan for virus signatures.
Process natural language.
Search for information using Google.
Search for markers in human genome
Search-and-replace in a word processors.
Validate data-entry fields (dates, email, URL, credit card)

19. Email Address Standards
There are acknowledged standards for what constitutes a valid
email address.
These are defined in the Request For Comments documents (RFCs)
The syntax of email addresses has been defined in various RFCs,
most notably RFC 822 and RFC 5322.
We u s e d R F C 5 3 2 2 , a s t h i s i s t h e l a t e s t s t a n d a r d .

20. Code Snippet
string pattern = @"^[a-z][a-z|0-9|]*([_][a-z|0-9]+)*([.][a-z|" +
@"0-9]+([_][a-z|0-9]+)*)?@[a-z][a-z|0-9|]*.([a-z]" +
@"[a-z|0-9]*(.[a-z][a-z|0-9]*)?)$";
System.Text.RegularExpressions.Match match =
Regex.Match(textBox1.Text.Trim(), pattern, RegexOptions.IgnoreCase);

21. Finite State Machine

22. ANY
Question?

23. Thanks