A computer is an electronic machine that processes raw data to give information as output.An electronic device that accepts data as input, and transforms it under the influence of a set of special instructions called Programs, to produce the desired output.A computer has an internal memory, which stores data & instructions temporarily awaiting processing, and even holds the intermediate result (information) before it is communicated to the recipients through theOutput devices.This book focuses on the development and testing of software and software systems It involves working with mathematical models, data analysis and security, algorithms, and computational theory.It involves working with mathematical models, data analysis and security, algorithms, and computational theory.