This book is of immense use for the students of BSC (CS), BSC (IT), B.Tech (CSE), B.Tech (IT), M.Tech (CSE) and M.Tech (IT) who involved in this field. This book is divided into five chapters and all topics are illustrated with clear diagrams, very simple language is used throughout the text to facilitate easy understanding of concepts, Students will find the parts in the earliest way that they can understand.We hope the book will serve its intended purpose and students will get benefit from it the maximum possible ways. We would like to thanks to all peoples who suggest our book and all the students who invoke this book, we hope that this new edition will serve a great knowledge, and will be immensely helpful to all students, who are often hard pressed of time.