1. 1Object-Oriented Program Development Using C++ Computer Science and Programming Languages Computers are ubiquitous Computer literacy is essential Computer science: computers as an object of study –Hardware –Software –Theory Algorithm development: the core of computer science

2. 2Object-Oriented Program Development Using C++ A Brief History of Computers Computational tools to manage time and space –Stone tablets and the abacus Mechanical calculators from Pascal and Leibniz Nineteenth century developments –The Jacquard Loom –Babbage’s Analytical Engine Mid-twentieth century –The ABC (Atanasoff-Berry Computer) –ENIAC, MARK I and EDSAC

3. 3Object-Oriented Program Development Using C++ Figure 1-1 Charles Babbage’s Analytical Engine

4. 4Object-Oriented Program Development Using C++ Figure 1-2 ENIAC (Courtesy IBM archives)

5. 5Object-Oriented Program Development Using C++ Computer Hardware Hardware: physical components of computer Von Neumann machine (architecture) –Main memory unit –Secondary Storage Devices –Central Processing Unit (CPU) –Input/output (I/O) devices Bit: fundamental bi-valued unit of memory Byte: grouping of eight bits

6. 6Object-Oriented Program Development Using C++ Figure 1-4 Basic Hardware Units of a Computer

7. 7Object-Oriented Program Development Using C++ Figure 1-5 A Pentium Microprocessor Chip

8. 8Object-Oriented Program Development Using C++ Figure 1-6 Internal Structure of a Hard Disk Drive

9. 9Object-Oriented Program Development Using C++ Programming Languages Programming language: set of rules and valid identifiers used to construct computer programs Computer program: set of instructions directing manipulation of data by hardware Software: a set of programs Low-level languages –Machine language: binary code –Assembly: first layer of symbolic abstraction

10. 10Object-Oriented Program Development Using C++ Figure 1-9 Assembly Programs Must Be Translated

11. 11Object-Oriented Program Development Using C++ Low- and High-Level Languages Low-level languages are close to hardware –Machine language touches circuits with binary code –Assembly Symbolic code in 1:1 correspondence with machine Programs assembled (converted) into machine code High-level languages –Syntax and semantics approach human languages –Examples: C, C++, Java, FORTRAN –Source code: is either interpreted or compiled

12. 12Object-Oriented Program Development Using C++ Figure 1-10 Creating an Executable C++ Program

13. 13Object-Oriented Program Development Using C++ Procedural and Object Orientations Procedural Orientation –Modules of code (procedures) transform data –Procedures known by different names Functions (C and C++) and methods (Java and C++) Object Orientation –Objects as software constructs modeling real things –Design origins: the GUI (graphical user interface) –Three defining characteristics Encapsulation, inheritance, polymorphism

14. 14Object-Oriented Program Development Using C++ Application and System Software Application software: set of programs that interface with the user System software –Manages internal operation of the physical device –Insulates user from hardware Operating System (OS): critical system software Manages system resources Supports concurrency Provides security and protection

15. 15Object-Oriented Program Development Using C++ The Development of C++ Post WWII programming language design goals: –Structure, usability, flexibility, and customization Early high-level languages oriented to procedures –Examples: FORTRAN, ALGOL, COBOL Rationalization through structured programming –Pascal and C C++ as a superset of C –Incorporates C language into object-oriented paradigm

16. 16Object-Oriented Program Development Using C++ Figure 1-11 Basic Procedural Operations

17. 17Object-Oriented Program Development Using C++ Figure 1-12 Fortran Was Developed for Scientific and Engineering Applications

18. 18Object-Oriented Program Development Using C++ Objects and Classes Objects model real world things and abstractions –GUI –Data packages Classes: design template or blueprint for object Skills to master in object-oriented programming –Designing classes –Employing objects in a program –Utilizing user-defined classes in standard template library (STL)

19. 19Object-Oriented Program Development Using C++ A Class is a Plan Class: plan with complete set of parts and instructions Classes can be analogized to recipes –Ingredients and method for preparation –Attributes and behaviors –A food dish is an instance of a recipe –An object is an instance of a class

20. 20Object-Oriented Program Development Using C++ Figure 1-15 Using Named Ingredients for Gary’s Sardine Spread

21. 21Object-Oriented Program Development Using C++ From Recipe to Class Class ingredients: data declaration section –Includes variable data type and name –Specific values typically assigned separately Class methods for preparation: methods section –Follows data declaration section –Typically divided into two sub-sections Methods declaration Methods definition (or implementation)

22. 22Object-Oriented Program Development Using C++ Figure 1-17 A Programming Plan for Displaying a Message

23. 23Object-Oriented Program Development Using C++ Figure 1-18 Basic C++ Class Syntax

24. 24Object-Oriented Program Development Using C++ A C++ Class Structure Class consists of a header and a body Basic header: contains class keyword and name Class body –Follows declaration of header –Enclosed by braces and ends with semicolon –Contents Comprised of declaration of data and methods May include definition of methods

25. 25Object-Oriented Program Development Using C++ Figure 1-19 The Structure of a C++ Class Named ShowFirstMessage

26. 26Object-Oriented Program Development Using C++ Figure 1-20 A Sample C++ Class

27. 27Object-Oriented Program Development Using C++ A First Program in C++ Classes and functions –Consist of identifiers: words and special symbols Reserved words Standard identifiers Programmer supplied words –Building blocks for an executable C++ program Standard template library (STL) –Contains programmer-defined classes –Example:

28. 28Object-Oriented Program Development Using C++ Figure 1-22 Creating a C++ Executable Program

29. 29Object-Oriented Program Development Using C++ Reserved Words Reserved word (keyword) –Predefined for (and restricted to) specific use Standard identifiers –Predefined for (but not restricted to) specific use Identifiers: combination of letters, digits, or underscores (_) –First character must be a letter or underscore (_) –Only letters, digits, or underscores may follow initial character –Blank spaces not allowed

30. 30Object-Oriented Program Development Using C++ Table 1-2 C++ Reserved Words

31. 31Object-Oriented Program Development Using C++ Table 1-3 Sample of Standard C++ Identifiers

32. 32Object-Oriented Program Development Using C++ The main Function main ( ) function: program casing main ( ) header consists of three parts –Return type –Name –Parameter (or argument) list (optional) Body of main enclose by braces { } –Programming logic (linked to classes and functions) –Return statement made up of keyword and value –Each statement inside the function must end with semi-colon

33. 33Object-Oriented Program Development Using C++ Figure 1-23 The Structure of a main Function

34. 34Object-Oriented Program Development Using C++ The cout Object cout object –cout derived from Console OUTput –Sends passed data to standard output display device Classic first program: Hello World –Comments identify programmer and contents –Includes header file called from STL –Namespace “std” identifies location of files –chief instruction: cout << “Hello World!”; “<<“ stands for insertion (put) symbol

35. 35Object-Oriented Program Development Using C++ Figure 1-25 The Output from Program 1-1

36. 36Object-Oriented Program Development Using C++ Programming Style Programs begin executing with int main ( ) Only one main ( ) function per program Recommend placement of syntactic elements –Opening braces directly below first letter of int –Closing brace follows return statement –One statement per line –Indentation represents program logic

37. 37Object-Oriented Program Development Using C++ Comments Comments may be placed anywhere in program Comments improve readability and maintainability Comments are ignored by compiler Two types of comments –Line: denoted by pair of opening forward slashes (//) –Block: opens with forward slash and asterisk and closes with asterisk and forward slash (/*…*/)