CHAPTER 6 PROGRAM DEVELOPMENT

CHAPTER 6 PROGRAM DEVELOPMENT

1. COMPUTER PROGRAM: series of instructions that directs computer to perform tasks

   • PROGRAMMING LANGUAGE: used to communicate instructions

2. (1) Low-level language

   • - Machine-dependent runs only on one type of computer
     • - Machine and assembly languages are low-level
       • MACHINE LANGUAGE: 1ST generation language that computer directly recognizes
         • ASSEMBLY: 2ND, a programmer writes instructions using symbolic instruction codes
           • PROCEDURAL LANGUAGE (3GL) : 3RD, a series of English-like words to write instructions
             • NON-PROCEDURAL LANGUAGE (SQL) : 4TH that enables users to access data in a database
             • COMPILER
               • - program that converts entire source program into machine language before executing it
                 • INTERPRETER
                   • - program that translates and executes one program code statement at a time
                     • - does not produce object program
                       • C
                         • - powerful language originally designed to write system software
                           • - requires professional programming skills
           • - Instructions made up of symbolic instruction codes, meaningful abbreviations and codes
             • -Source program contains code to be converted to machine language
         • - Uses a series of binary digits (1s and 0s) with a combination of numbers

3. (2) High-level language

   • - Often machine-independent can run on many different types of computers and operating systems

4. (3) Object-Oriented Programming Languages

   • - Used to implement object-oriented design
     • OBJECT: item that contains data and procedures that act on data
       • - Major benefit is ability to reuse and modify existing objects
         • - Event-driven checks for responds to set of events
           • EVENT: action to which program responds
             • JAVA
               • - developed by Sun Microsystems
                 • - uses just-in-time (JIT) compiler to convert bytecode into machine-dependent code
             • C++
               • - includes all elements of C, plus additional features
                 • - used to develop database and Web applications
             • 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)
             • VISUAL PROGRAMMING LANGUAGE
               • - developers to drag and drop objects to build programs
                 • - provides visual or graphical interface for creating source code
                   • - used in RAD (rapid application development) environment
                     • - programmer writes and imolements program implements program in segments
             • VISUAL STUDIO
               • - NET set of tech that allows program to run on Internet
                 • - Comprised of Visual Basic, Visual C++, and Visual C#
             • DELPHI
               • - powerful program development tool
                 • - ideal for large-scale enterprise and Web applications
             • POWER BUILDER
               • - another powerful visual programming tool
                 • - best suited for Web-based and large-scale enterprise object-oriented applications

5. (4) Other Programming Languages

   • Nonprocedural Languages
     • - English instructions/interacts with a visual environment to retrieve data from files or a database
       • RPG (Report Program Generator)
         • - used for generating reports, accessing data, and updating data
           • 4GL (fourth-generation language)
             • - allows access to data in database
               • - popular 4GL is SQL, query language that allows users to manage data in relational DBMS
   • Program Development Tools
     • - programs designed to assist both programmers and users in creating programs
   • Ada
     • ALGOL
       • APL
         • BASIC
           • Forth
             • FORTRAN
               • Hypertalk
                 • LISP
                   • Logo
                     • Modula-2
                       • Pascal
                         • PILOT
                           • PL/1
                             • Prolog
     • Smalltalk

6. (5) Other Program/Development Tools

   • Application Generator
     • - program that creates source code/machine code from specification
       • - consists of report writer, form, and menu generator
         • Macro
           • - series of staments that instructs an application how to complete a task

7. (6) Web Page Development

   • HTML (Hypertext Markup Language) : used to create Web pages
     • - Script interpreted program that runs on client
       • - Applet usually runs on client, but is compiled
         • - Servlet applet that runs on server
           • - Active X control small program that runs on client
             • - Counter tracks number of visitors to Web site
               • - Image map graphic image that points to URL
                 • - Processing form collects data from visitors to Web site
   • common gateway interface (CGI)
     • - communications standard that defines how Web server communicates with outside sources
       • CGI script: program that manages sending and receiving across CGI
         • JavaScript
           • Perl (Practical Extraction and Report Language)
             • PHP (Hypertext Preprocessor)
               • Rexx (Restructured eXtended eXecutor)
                 • TCL (Tool Command Language)
                   • VBScript (Visual Basic, Scripting Edition)
   • DHTML (Dynamic HTML) : allows developers to include more graphical interest and interactivity in Web page
     • XHTML (Extensible HTML) : enables Web sites to be displayed more easily on microbrowsers
       • XML (Extensible Markup Language) : allows developers to create customized tags
         • WML (Wireless Markup Language) : allows developers to design pages specifically for microbrovsers
           • Ajax
             • - stands for Asynchronous Java Script and XML
           • Ruby on Rails (ROR)
             • - open source framework that provides tech for developing object-oriented
   • Web Page Authoring Software
     • - creates sophisticated Web pages without using HTML

8. (6) Program Development Cycle

   • - steps programmers use to build computer programs
     • ANALYZE: define the problem
       • DESIGN SOLUTION: plan the solution to the problrm
         • VALIDATE DESIGN: select the objects
           • IMPLEMENT DESIGN: translate the algorithm in the programming language
             • TEST SOLUTION: locate and fix any errors in the program
               • DOCUMENT SOLUTION: organize all the material that describes the program

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