Hashim Naseer Lokasher 11014119-129

Muazzam Ali Sundhu 11014119-099Haseeb Mehmood 11014119-089

Gohar Naseer 11014119-087Muhammad Qasim Ali 11014119-128

THEORY OF AUTOMATA

PROJECT TITLE: EMAIL VALIDATOR

Introduction

Email Validator

Email Validator

What does Validation means?

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).

Email Validation

So,

Email Validation means to validate and check an email address.

Our Project

Is a email validator, whichValidates an Email AddressCheck the grammar and syntaxCan be used in Data Entry forms and Applications

Screenshot

C# Programming Language is used for the development of this application.

WinForm and Regular Expressions class is also used

Program Working

Email Validator

So, What is a Valid Email Address?

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

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.

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.

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.

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.

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

?

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

Regular Expression for Email Validation

Myname@mycompany.com can be validated as

Myname @ mycompany com.

We compared the given email address with the upper RegEx to validate it is synthetically

correct or not.

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)

Regular Expressions

Regular Expressions can be used toTest 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)

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 used RFC 5322 , as this is the latest standard.

Code Snippetstring 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);

Finite State Machine

ANYQuestion?

Thanks