Discovering Computers 2008 Chapter 13 Programming Languages and Program Development

Chapter 13 Objectives Next Describe various ways to develop Web pages including HTML, scripting languages, DHTML, XML, WML, and Web page authoring software Differentiate between machine and assembly languages Identify and discuss the purpose of procedural programming languages Identify and discuss the characteristics of object-oriented programming languages and program development tools Identify the uses of other programming languages and other program development tools Identify the uses of popular multimedia authoring programs List the six steps in the program development cycle Differentiate between structured design and object-oriented design Explain the basic control structures and design tools used in designing solutions to programming problems

Computer Programs and Programming Languages What is a computer program? p. 664 Fig Next  Series of instructions that directs computer to perform tasks  Programming language—used to communicate instructions

Computer Programs and Programming Languages What are low-level languages and high-level languages? p. 665 Next High-level language Low-level language Machine-dependent runs only on one type of computer Often machine-independent can run on many different types of computers and operating systems Machine and assembly languages are low-level

Low-Level Languages What is machine language? p. 665 Fig Next  Only language computer directly recognizes  Uses a series of binary digits (1s and 0s) with a combination of numbers and letters that represent binary digits

Low-Level Languages What is assembly language? p. 666 Fig Next  Instructions made up of symbolic instruction codes, meaningful abbreviations and codes  Source program contains code to be converted to machine language

third-generation language (3GL) Often called third-generation language (3GL) Procedural Languages What is a procedural language? p. 666 Next Uses series of English-like words to write instructions Programmer writes instructions that tell computer what to accomplish and how to do it

Procedural Languages What is a compiler? p. 667 Fig Next  Program that converts entire source program into machine language before executing it

Procedural Languages What is an interpreter? p. 667 Fig Next  Program that translates and executes one program code statement at a time  Does not produce object program

Procedural Languages What is COBOL? p. 668 Next  Designed for business applications  English-like statements make code easy to read, write, and maintain  COmmon Business-Oriented Language Click to view Web Link, click Chapter 13, Click Web Link from left navigation, then click COBOL below Chapter 13

Procedural Languages What is C? p. 668 Fig and 13-7 Next  Powerful language originally designed to write system software  Requires professional programming skills COBOL C

Object-Oriented Programming Languages What is an object-oriented programming (OOP) language? p. 669 Next Used to implement object-oriented design Major benefit is ability to reuse existing objects Event-driven— checks for and responds to set of events Java, C++, C#, and Visual Basic are complete object-oriented languages Object is item that contains data and procedures that act on data Event is action to which program responds

Object-Oriented Programming Languages What is Java? p. 669 Fig Next  Developed by Sun Microsystems  Similar to C++ but uses just-in-time (JIT) compiler to convert source code into machine code Click to view Web Link, click Chapter 13, Click Web Link from left navigation, then click Java below Chapter 13

Object-Oriented Programming Languages What is C++? p. 670 Fig Next  Includes all elements of C, plus additional features for working with object-oriented concepts  Used to develop database and Web applications Click to view Web Link, click Chapter 13, Click Web Link from left navigation, then click C++ below Chapter 13

Object-Oriented Programming Languages What is C#? p. 670 Next  Object-oriented programming language based on C++  Accepted as a standard for Web applications and XML-based Web services  Uses a JIT compiler  Resulting code is called Microsoft Intermediate Language (MSIL) Click to view Web Link, click Chapter 13, Click Web Link from left navigation, then click C# below Chapter 13

Object-Oriented Programming Languages What is a visual programming language? p. 669 and 673 Next Programmer writes and implements program in segments Visual programming environment (VPE) allows developers to drag and drop objects to build programs Often used in RAD (rapid application development) environment Sometimes called fifth-generation language Provides visual or graphical interface for creating source code

Object-Oriented Programming Languages What is Visual Studio? p Fig Next .NET is set of technologies that allows program to run on Internet  Comprised of Visual Basic, Visual C++, Visual C#, and Visual J# Click to view Web Link, click Chapter 13, Click Web Link from left navigation, then click Visual Studio Tools for Office below Chapter 13 Step 1. The developer designs the user interface. Step 2. The developer assigns properties to each object on the form. Step 3. The developer writes code to define the action of each command button. Step 4. The developer tests the program.

Object-Oriented Programming Languages What is Delphi? p. 672 Fig Next  Powerful visual programming tool  Ideal for large-scale enterprise and Web applications

Object-Oriented Programming Languages What is PowerBuilder? p. 673 Fig Next  Another powerful visual programming tool  Best suited for Web-based and large-scale enterprise object-oriented applications

Other Programming Languages  What are nonprocedural languages and program development tools? p. 669 and 674 Next Nonprocedural Language The programmer writes English- like instructions or interacts with a visual environment to retrieve data from files or a database Program Development Tools User-friendly programs designed to assist both programmers and users in creating programs

Other Programming Languages What is RPG (Report Program Generator)? p. 674 Fig Next  Nonprocedural language used for generating reports, performing computations, and updating files

Other Programming Languages What is a fourth-generation language (4GL)? p. 674 Fig Next  Nonprocedural language that allows access to data in database  Popular 4GL is SQL, query language that allows users to manage data in relational DBMS

Other Programming Languages What are other available programming languages? p. 675 Fig Next ALGOLALGOLADAADAAPLAPL BASICBASICHYPERTALKHYPERTALKFORTRANFORTRANFORTHFORTH LISPLISPMODULA-2MODULA-2LOGOLOGO PASCALPASCALPROLOGPROLOGPL/1PL/1PILOTPILOT SMALLTALKSMALLTALK

Other Program Development Tools What is an application generator? p. 676 Fig Next  Program that creates source code or machine code from specification  Consists of report writer, form, and menu generator  Form provides areas for entering data

Other Program Development Tools What is a macro? p Fig Next  Series of statements that instructs an application how to complete a task Click to view Web Link, click Chapter 13, Click Web Link from left navigation, then click Macros below Chapter 13

Web Page Development What is HTML (Hypertext Markup Language)? p. 678 Fig Next  Used to create Web pages Click to view Web Link, click Chapter 13, Click Web Link from left navigation, then click HTML below Chapter 13

Web Page Development How are special effects and interactive elements added to a Web page? p. 679 Next Counter Counter tracks number of visitors to Web site Image map Image map graphic image that points to URL Script Script interpreted program that runs on client Applet Applet usually runs on client, but is compiled Processing form Processing form collects data from visitors to Web site Servlet Servlet applet that runs on server ActiveX control ActiveX control small program that runs on client

Web Page Development What is the common gateway interface (CGI)? p Fig Next  Communications standard that defines how Web server communicates with outside sources  CGI script—program that manages sending and receiving across CGI

Web Page Development What is a scripting language? p Fig Next  Typically easy to learn and use  JavaScript  Perl (Practical Extraction and Report Language)  PHP (PHP: Hypertext Preprocessor)  Rexx (Restructured eXtended eXecutor)  TCL (Tool Command Language)  VBScript (Visual Basic, Scripting Edition)

Web Page Development What is dynamic HTML (DHTML)? p. 682 Fig Next  Allows developers to include more graphical interest and interactivity in Web page Click to view Web Link, click Chapter 13, Click Web Link from left navigation, then click DHTML below Chapter 13

Web Page Development What are XHTML, XML, and WML? p Next XHTML XHTML (Extensible HTML) enables Web sites to be displayed more easily on microbrowsers XML XML (Extensible Markup Language) allows developers to create customized tags WML WML (Wireless Markup Language) allows developers to design pages specifically for microbrowsers Includes features of HTML and XML Many PDAs and smart phones use WML as their markup language Server sends entire record to client, enabling client to do much of processing without going back to server RSS 2.0

Web Page Development What is Ajax? p. 683 Next  Stands for Asynchronous JavaScript and XML  Method of creating interactive Web applications designed to provide immediate response  Combines JavaScript, HTML or XHTML, and XML  Google Maps and Flickr use Ajax Click to view Web Link, click Chapter 13, Click Web Link from left navigation, then click Ajax below Chapter 13

Web Page Development What is Ruby on Rails (RoR)? p. 683 Next  Also called Rails  Open source framework that provides technologies for developing object-oriented, database-driven Web sites  Ruby is derived from a variety of languages, including Ada, LISP, Perl, and Smalltalk

Flash Expression Web Web Page Development What is Web page authoring software? p. 683 Next  Creates sophisticated Web pages without using HTML  Generates HTML Dreamweaver

Multimedia Program Development What is multimedia authoring software? p. 684 Fig Next  Combines text, graphics, animation, audio, and video into interactive presentation  Used for computer- based training (CBT) and Web-based training (WBT)  Software includes Toolbook, Authorware, and Director

The Program Development Cycle What is the program development cycle? p Fig Next  Steps programmers use to build computer programs  Programming team—Group of programmers working on program

Step 1 — Analyze Requirements What is involved in analyzing the requirements? p. 686 Fig Next 1.Review requirements 2.Meet with systems analyst and users 3.Identify input, output, processing, and data components  IPO chart— Identifies program’s inputs, outputs, and processing steps

Programmer begins with general design and moves toward detailed design Step 2 — Design Solution What is involved in designing the solution? p. 687 Next Object-oriented design Structured design, sometimes called top-down design Two approaches Devise solution algorithm, step-by-step procedure to solve problem

Step 2 — Design Solution What is a hierarchy chart? p. 687 Fig Next  Shows program modules graphically  Also called structure chart

Step 2 — Design Solution What is object-oriented (OO) design? p. 688 Fig Next  Programmer packages data and procedure into single unit, an object  Objects are grouped into classes  Class diagram represents hierarchical relationships of classes graphically Click to view Web Link, click Chapter 13, Click Web Link from left navigation, then click Object-Oriented Design below Chapter 13

Step 2 — Design Solution What is a sequence control structure? p. 688 Fig Next  Control structure that shows actions following each other in order  Control structure depicts logical order of program instructions

Step 2 — Design Solution What is a selection control structure? p. 689 Fig Next  Tells program which action to take, based on a certain condition  Two types  Case control structure  If-then-else control structure—yields one of two possibilities: true or false

Step 2 — Design Solution What is a case control structure? p. 689 Fig Next  Yields one of three or more possibilities

Step 2 — Design Solution What is a repetition control structure? p Figs –13-31 Next  Enables program to perform one or more actions repeatedly  Do-while control structure—repeats as long as condition is true  Do-until control structure—repeats until condition is true

Step 2 — Design Solution What is a program flowchart? p. 690 Fig Next  Graphically shows logic in solution algorithm

Step 2 — Design Solution What is an example of a flowchart? p. 691 Fig Next

Step 2 — Design Solution What is flowcharting software? p Fig Next  Used by programmers to develop flowcharts Click to view Web Link, click Chapter 13, Click Web Link from left navigation, then click Flowcharting Software below Chapter 13

Step 2 — Design Solution What is pseudocode? p. 690 and 692 Fig Next  Uses condensed form of English to convey program logic

Step 3 — Validate Design What is involved in validating the design? p. 693 Next Check program design for accuracy Logic error Logic error design flaw that causes inaccurate results Test data Test data sample data that mimics real data that program will process Programmer checks logic for correctness and attempts to uncover logic errors Desk check Desk check programmers use test data to step through logic Inspection systems analyst reviews deliverables during the system development cycle

Step 4 — Implement Design What is implementation? p Fig Next  Writing the code that translates the design into a program  Syntax—rules that specify how to write instructions  Comments—program documentation  Extreme programming (XP)—coding and testing as soon as requirements are defined

Step 5 — Test Solution What is involved in testing the solution? p Next Ensure program runs correctly and is error free Debugging—locating and correcting syntax and logic errors, or bugs Test copy of program, called beta, sometimes used to find bugs

Step 6 — Document Solution What is involved in documenting the solution? p. 696 Next  Programmer performs two activities Reviews program code—removes dead code, program instructions that program never executes Reviews documentation

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Summary of Programming Languages and Program Development Various programming languages used to write and develop computer programs The program development cycle and the tools used to make this process efficient Web development and multimedia development tools Chapter 13 Complete