Java语言程序设计 参考资料1.ppt

Chapter 1 – Introduction to Computers, the Internet, and the Web Chapter 1 – Introduction to Computers, the Internet, and the Web 1.1 Introduction Java How to Program, Fourth Edition Java 2 Standard Edition Object-oriented programming 1.2 What Is a Computer? Computer Performs computations and makes logical decisions Millions / billions times faster than human beings Computer programs Sets of instructions for which computer processes data Hardware Physical devices of computer system Software Programs that run on computers 1.3 Computer Organization Six logical units of computer system Input unit Mouse, keyboard Output unit Printer, monitor, audio speakers Memory unit RAM Arithmetic and logic unit (ALU) Performs calculations Central processing unit (CPU) Supervises operation of other devices Secondary storage unit Hard drives, floppy drives 1.4 Evolution of Operating Systems Batch processing One job (task) at a time Operating systems developed Programs to make computers more convenient to use Switch jobs easier Multiprogramming “Simultaneous” jobs Timesharing operating systems 1.5 Personal, Distributed and Client/Server Computing Personal computing Computers for personal use Distributed computing Computing performed among several computers Client/server computing Servers offer common store of programs and data Clients access programs and data from server 1.6 Machine Languages, Assembly Languages and High-Level Languages Machine language “Natural language” of computer component Machine dependent Assembly language English-like abbreviations represent computer operations Translator programs convert to machine language High-level language Allows for writing more “English-like” instructions Contains commonly used mathematical operations Compiler convert to machine language Interpreter Execute high-level language programs without compilation 1.7 History of C++ C++ Evolved from C Evolved from BCPL and B Provides object-oriented programming capabilities Objects R