Minor Project Report

A PROJECT REPORT ON LEXICAL ANALYZER SESSION: 2008 - 2009

Guided By:

Submitted By:

Ms. Deepti Arora

Ankita Verma (B.E. VIIth sem I.T.)

Submitted to: Department of Information Technology Laxmi Devi Institute of Engineering & Technology, Alwar (Raj.) University of Rajasthan

INDEX 1. Project description

1.1

Objective of the project

2. Project contents 2.1

Software development life cycle

2.2

Study and formulation

2.3

Project category

2.4

Platform (technology/tools)

2.5

Software and hardware used

2.6

Feasibility

2.7

System design

2.8

Data flow diagram

2.9

Entity relationship diagram

2.10 Testing 2.10.1testing methodology 2.10.2testing strategy 2.11 System security 2.12 Implementation and maintenance 2.13 Evaluation 2.14 code 3. Advantages and disadvantages 4. Conclusion 5. reference

ACKNOWLEDGEMENT We thank Mr. Sudhir Pathak, Head of Department, Department of Computer Science and Information Technology, LIET Alwar (Raj.) for his guidance and co-operation. We also acknowledge the advice and help given to us by Ms. Deepti Arora. We would like to extend our gratitude to the entire faculty and staff of the Department of CS & IT, LIET Alwar (Raj.), who stood by us in all pits and falls we had to face during the development phase of this project.

CERTIFICATE OF APPROVAL SESSION: 2008-2009

This is o certify that Ms. Ankita Verma, Ms. Harshi Yadav, Ms. Sameeksha Chauhan have successfully completed the project entitled

“LEXICAL ANALYZER” Under the able guidance of Ms. Deepti Arora towards the partial fulfillment of the of Bachelor’s degree course in Information Technology.

Head of Department

Guide By:

Mr. Sudhir Pathak

Ms. Deepti Arora

Preface The lexical analyzer is responsible for scanning the source input file and translating lexemes into small objects that the compiler can easily process. These small values are often called “tokens”. The lexical analyzer is also responsible for converting sequences of digits in to their numeric form as well as processing other literal constants, for removing comments and whitespace from the source file, and for taking care of many other mechanical details. The lexical analyzer reads a string of characters and checks if a valid token in the grammar. Lexical analysis terminology: • Token:  Terminal symbol in a grammar  Classes of sequences of characters with a collective meaning  Constants, operators, punctuations, keywords. • Lexeme:  Character sequence matched by an instance of the token.

Project Description

Lexical analyzer converts stream of input characters into a stream of tokens. The different tokens that our lexical analyzer identifies are as follows: KEYWORDS: int, char, float, double, if, for, while, else, switch, struct, printf, scanf, case, break, return, typedef, void IDENTIFIERS: main, fopen, getch etc NUMBERS: positive and negative integers, positive and negative floating point numbers. OPERATORS: +, ++, -, --, ||, *, ?, /, >, >=,