cpphtp4_PPT_01.pptx

1 Chapter 1 – Introduction to Computers and C++ Programming Outline 1.1 Introduction 1.2 What is a Computer? 1.3 Computer Organization 1.4 Evolution of Operating Systems 1.5 Perso...

1 Chapter 1 – Introduction to Computers and C++ Programming Outline 1.1 Introduction 1.2 What is a Computer? 1.3 Computer Organization 1.4 Evolution of Operating Systems 1.5 Personal Computing, Distributed Computing and Client/Server Computing 1.6 Machine Languages, Assembly Languages, and High-Level Languages 1.7 History of C and C++ 1.8 C++ Standard Library 1.9 Java 1.10 Visual Basic, Visual C++ and C# 1.11 Other High-Level Languages 1.12 Structured Programming 1.13 The Key Software Trend: Object Technology 1.14 Basics of a Typical C++ Environment 1.15 Hardware Trends  2003 Prentice Hall, Inc. All rights reserved.  2 Chapter 1 – Introduction to Computers and C++ Programming Outline 1.16 History of the Internet 1.17 History of the World Wide Web 1.18 World Wide Web Consortium (W3C) 1.19 General Notes About C++ and This Book 1.20 Introduction to C++ Programming 1.21 A Simple Program: Printing a Line of Text 1.22 Another Simple Program: Adding Two Integers 1.23 Memory Concepts 1.24 Arithmetic 1.25 Decision Making: Equality and Relational Operators 1.26 Thinking About Objects: Introduction to Object Technology and the Unified Modeling Language  2003 Prentice Hall, Inc. All rights reserved.  3 1.1 Introduction Software – Instructions to command computer to perform actions and make decisions Hardware Standardized version of C++ – United States American National Standards Institute (ANSI) – Worldwide International Organization for Standardization (ISO) Structured programming Object-oriented programming  2003 Prentice Hall, Inc. All rights reserved.  4 1.2 What is a Computer? Computer – Device capable of performing computations and making logical decisions Computer programs – Sets of instructions that control computer’s processing of data Hardware – Various devices comprising computer Keyboard, screen, mouse, disks, memory, CD-ROM, processing units, … Software – Programs that run on computer  2003 Prentice Hall, Inc. All rights reserved.  5 1.3 Computer Organization Six logical units of computer 1. Input unit “Receiving” section Obtains information from input devices – Keyboard, mouse, microphone, scanner, networks, … 2. Output unit “Shipping” section Takes information processed by computer Places information on output devices – Screen, printer, networks, … – Information used to control other devices  2003 Prentice Hall, Inc. All rights reserved.  6 1.3 Computer Organization Six logical units of computer 3. Memory unit Rapid access, relatively low capacity “warehouse” section Retains information from input unit – Immediately available for processing Retains processed information – Until placed on output devices Memory, primary memory 4. Arithmetic and logic unit (ALU) “Manufacturing” section Performs arithmetic calculations and logic decisions  2003 Prentice Hall, Inc. All rights reserved.  7 1.3 Computer Organization Six logical units of computer 5. Central processing unit (CPU) “Administrative” section Supervises and coordinates other sections of computer 6. Secondary storage unit Long-term, high-capacity “warehouse” section Storage – Inactive programs or data Secondary storage devices – Disks Longer to access than primary memory Less expensive per unit than primary memory  2003 Prentice Hall, Inc. All rights reserved.  8 1.4 Evolution of Operating Systems Early computers – Single-user batch processing Only one job or task at a time Process data in groups (batches) Decks of punched cards Operating systems – Software systems – Manage transitions between jobs – Increased throughput Amount of work computers process  2003 Prentice Hall, Inc. All rights reserved.  9 1.4 Evolution of Operating Systems Multiprogramming – Many jobs or tasks sharing computer’s resources – “Simultaneous” operation of many jobs Timesharing – 1960s – Special case of multiprogramming – Users access computer through terminals Devices with keyboards and screens Dozens, even hundreds of users – Perform small portion of one user’s job, then moves on to service next user – Advantage: User receives almost immediate responses to requests  2003 Prentice Hall, Inc. All rights reserved.  10 1.5 Personal Computing, Distributed Computing, and Client/Server Computing Personal computers – 1977: Apple Computer – Economical enough for individual – 1981: IBM Personal Computer – “Standalone” units Computer networks – Over telephone lines – Local area networks (LANs) Distributed computing – Organization’s computing distributed over networks  2003 Prentice Hall, Inc. All rights reserved.  11 1.5 Personal Computing, Distributed Computing, and Client/Server Computing Workstations – Provide enormous capabilities – Information shared across networks Client/server computing – File servers Offer common store of programs and data – Client computers Access file servers across network UNIX, Linux, Microsoft’s Window-based systems  2003 Prentice Hall, Inc. All rights reserved.  12 1.6 Machine Languages, Assembly Languages, and High-level Languages Three types of computer languages 1. Machine language Only language computer directly understands “Natural language” of computer Defined by hardware design – Machine-dependent Generally consist of strings of numbers – Ultimately 0s and 1s Instruct computers to perform elementary operations – One at a time Cumbersome for humans Example: +1300042774 +1400593419 +1200274027  2003 Prentice Hall, Inc. All rights reserved.  13 1.6 Machine Languages, Assembly Languages, and High-level Languages Three types of computer languages 2. Assembly language English-like abbreviations representing elementary computer operations Clearer to humans Incomprehensible to computers – Translator programs (assemblers) Convert to machine language Example: LOAD BASEPAY ADD OVERPAY STORE GROSSPAY  2003 Prentice Hall, Inc. All rights reserved.  14 1.6 Machine Languages, Assembly Languages, and High-level Languages Three types of computer languages 3. High-level languages Similar to everyday English, use common mathematical notations Single statements accomplish substantial tasks – Assembly language requires many instructions to accomplish simple tasks Translator programs (compilers) – Convert to machine language Interpreter programs – Directly execute high-level language programs Example: grossPay = basePay + overTimePay  2003 Prentice Hall, Inc. All rights reserved.  15 1.7 History of C and C++ History of C – Evolved from two other programming languages BCPL and B – “Typeless” languages – Dennis Ritchie (Bell Laboratories) Added data typing, other features – Development language of UNIX – Hardware independent Portable programs – 1989: ANSI standard – 1990: ANSI and ISO standard published ANSI/ISO 9899: 1990  2003 Prentice Hall, Inc. All rights reserved.  16 1.7 History of C and C++ History of C++ – Extension of C – Early 1980s: Bjarne Stroustrup (Bell Laboratories) – “Spruces up” C – Provides capabilities for object-oriented programming Objects: reusable software components – Model items in real world Object-oriented programs – Easy to understand, correct and modify – Hybrid language C-like style Object-oriented style Both  2003 Prentice Hall, Inc. All rights reserved.  17 1.8 C++ Standard Library C++ programs – Built from pieces called classes and functions C++ standard library – Rich collections of existing classes and functions “Building block approach” to creating programs – “Software reuse”  2003 Prentice Hall, Inc. All rights reserved.  18 1.9 Java Java – 1991: Sun Microsystems Green project – 1995: Sun Microsystems Formally announced Java at trade show – Web pages with dynamic and interactive content – Develop large-scale enterprise applications – Enhance functionality of web servers – Provide applications for consumer devices Cell phones, pagers, personal digital assistants, …  2003 Prentice Hall, Inc. All rights reserved.  19 1.10 Visual Basic, Visual C++ and C# BASIC – Beginner’s All-Purpose Symbolic Instruction Code – Mid-1960s: Prof. John Kemeny and Thomas Kurtz (Dartmouth College) Visual Basic – 1991 Result of Microsoft Windows graphical user interface (GUI) – Developed late 1980s, early 1990s – Powerful features GUI, event handling, access to Win32 API, object-oriented programming, error handling – Visual Basic.NET  2003 Prentice Hall, Inc. All rights reserved.  20 1.10 Visual Basic, Visual C++ and C# Visual C++ – Microsoft’s implementation of C++ Includes extensions Microsoft Foundation Classes (MFC) Common library – GUI, graphics, networking, multithreading, … – Shared among Visual Basic, Visual C++, C#.NET platform – Web-based applications Distributed to great variety of devices – Cell phones, desktop computers – Applications in disparate languages can communicate  2003 Prentice Hall, Inc. All rights reserved.  21 1.10 Visual Basic, Visual C++ and C# C# – Anders Hejlsberg and Scott Wiltamuth (Microsoft) – Designed specifically for.NET platform – Roots in C, C++ and Java Easy migration to.NET – Event-driven, fully object-oriented, visual programming language – Integrated Development Environment (IDE) Create, run, test and debug C# programs Rapid Application Development (RAD) – Language interoperability  2003 Prentice Hall, Inc. All rights reserved.  22 1.11 Other High-level Languages FORTRAN – FORmula TRANslator – 1954-1957: IBM – Complex mathematical computations Scientific and engineering applications COBOL – COmmon Business Oriented Language – 1959: computer manufacturers, government and industrial computer users – Precise and efficient manipulation of large amounts of data Commercial applications  2003 Prentice Hall, Inc. All rights reserved.  23 1.11 Other High-level Languages Pascal – Prof. Niklaus Wirth – Academic use  2003 Prentice Hall, Inc. All rights reserved.  24 1.12 Structured Programming Structured programming (1960s) – Disciplined approach to writing programs – Clear, easy to test and debug, and easy to modify Pascal – 1971: Niklaus Wirth Ada – 1970s - early 1980s: US Department of Defense (DoD) – Multitasking Programmer can specify many activities to run in parallel  2003 Prentice Hall, Inc. All rights reserved.  25 1.13 The Key Software Trend: Object Technology Objects – Reusable software components that model real world items – Meaningful software units Date objects, time objects, paycheck objects, invoice objects, audio objects, video objects, file objects, record objects, etc. Any noun can be represented as an object – More understandable, better organized and easier to maintain than procedural programming – Favor modularity Software reuse – Libraries MFC (Microsoft Foundation Classes) Rogue Wave  2003 Prentice Hall, Inc. All rights reserved.  26 1.14 Basics of a Typical C++ Environment C++ systems – Program-development environment – Language – C++ Standard Library  2003 Prentice Hall, Inc. All rights reserved.  27 1.14 Basics of a Typical C++ Environment Program is created in Editor Disk Phases of C++ Programs: the editor and stored on disk. Preprocessor Preprocessor program 1. Edit Disk processes the code. Compiler creates Compiler object code and stores 2. Preprocess Disk it on disk. Linker links the object Linker 3. Compile Disk code with the libraries, creates a.out and Primary stores it on disk Memory 4. Link Loader Loader puts program 5. Load Disk.... in memory... 6. Execute Primary Memory CPU CPU takes each instruction and executes it, possibly storing new data.... values as the program.. executes.  2003 Prentice Hall, Inc. All rights reserved.  28 1.14 Basics of a Typical C++ Environment Input/output – cin Standard input stream Normally keyboard – cout Standard output stream Normally computer screen – cerr Standard error stream Display error messages  2003 Prentice Hall, Inc. All rights reserved.  29 1.15 Hardware Trends Capacities of computers – Approximately double every year or two – Memory used to execute programs – Amount of secondary storage Disk storage Hold programs and data over long term – Processor speeds Speed at which computers execute programs  2003 Prentice Hall, Inc. All rights reserved.  30 1.16 History of the Internet Late 1960s: ARPA – Advanced Research Projects Agency Department of Defense – ARPAnet – Electronic mail (e-mail) Packet switching – Transfer digital data via small packets – Allow multiple users to send/receive data simultaneously over same communication paths No centralized control – If one part of network fails, other parts can still operate  2003 Prentice Hall, Inc. All rights reserved.  31 1.16 History of the Internet TCP/IP – Transmission Control Protocol (TCP) Messages routed properly Messages arrived intact – Internet Protocol (IP) Communication among variety of networking hardware and software Current architecture of Internet Bandwidth – Carrying capacity of communications lines  2003 Prentice Hall, Inc. All rights reserved.  32 1.17 History of the World Wide Web World Wide Web – 1990: Tim Berners-Lee (CERN) – Locate and view multimedia-based documents – Information instantly and conveniently accessible worldwide – Possible worldwide exposure Individuals and small businesses – Changing way business done  2003 Prentice Hall, Inc. All rights reserved.  33 1.18 World Wide Web Consortium (W3C) World Wide Web Consortium (W3C) – 1994: Tim Berners-Lee – Develop nonproprietary, interoperable technologies – Standardization organization – Three hosts Massachusetts Institute of Technology (MIT) France’s INRIA (Institut National de Recherche en Informatique et Automatique) Keio University of Japan – Over 400 members Primary financing Strategic direction  2003 Prentice Hall, Inc. All rights reserved.  34 1.18 World Wide Web Consortium (W3C) Recommendations – 3 phases Working Draft – Specifies evolving draft Candidate Recommendation – Stable version that industry can begin to implement Proposed Recommendation – Considerably mature Candidate Recommendation  2003 Prentice Hall, Inc. All rights reserved.  35 1.19 General Notes About C++ and This Book Book geared toward novice programmers – Stress programming clarity – C and C++ are portable languages Portability – C and C++ programs can run on many different computers Compatibility – Many features of current versions of C++ not compatible with older implementations  2003 Prentice Hall, Inc. All rights reserved.  36 1.20 Introduction to C++ Programming C++ language – Facilitates structured and disciplined approach to computer program design Following several examples – Illustrate many important features of C++ – Each analyzed one statement at a time Structured programming Object-oriented programming  2003 Prentice Hall, Inc. All rights reserved.  37 1.21 A Simple Program: Printing a Line of Text Comments – Document programs – Improve program readability – Ignored by compiler – Single-line comment Begin with // Preprocessor directives – Processed by preprocessor before compiling – Begin with #  2003 Prentice Hall, Inc. All rights reserved.  38 1 // Fig. 1.2: fig01_02.cpp 2 // A first program in C++. Single-line comments. Outline 3 Function main #include returns an 4 integer Left brace { begins Preprocessor value. function directive to fig01_02.cpp 5 // function main begins body. program include execution Function input/output Statements main appears stream end with a(1 of 1) 6 int main() header exactly once file. in every C++ semicolon ;. 7 { 8 program.. std::cout