This textbook has been written according to the new revised syllabus of West Bengal University of Technology for the second year (fourth semester) B. Tech. (CSE and IT) students. It consists of fifteen chapters. This book can also be treated as a supplementary book for B.E./B.Tech. students of other universities. This book contains various types of problems along with worked out model problems which are essential to the Engineering/Technological students. Multiple choice questions with answers provided in this textbook will be helpful for GATE and other competitive examinations.