Program Development and Programming Languages

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Chapter 13

• Program Development and Programming Languages

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Learning Objectives

• Identify and describe the activities involved in
  the program development life cycle (PDLC).
• Understand what constitutes good program design.
• Describe several tools that can be used by
  computer professionals when designing a program.
• Explain the three basic control structures and
  how they can be used to control program flow
  during execution.

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Learning Objectives, contd.

• Explain some of the activities involved with
  coding, debugging, maintaining, documenting, and
  ensuring the quality of programs.
• List tools that can be used to speed up or
  otherwise facilitate the program development
  process.
• Identify programming language options available
  to code programs.
• List some Web-based languages that can be used
  instead of, or in addition to, programming
  languages to create Web content.

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Overview

• This chapter covers
• The program development life cycle
• Programming languages, what they are and some of
  the most popular ones

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The Program Development Life Cycle
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Problem Analysis

• During problem analysis, a systems analyst and
  programmer review specifications and talk with
  users to fully understand what the software
  should do.
• Documentation consists of program specifications,
  timetable, which language will be used, how the
  program will be tested, and what documentation is
  required.

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Program Design

• Program design stage where program
  specifications are expanded into a complete
  design of the new program.
• Structured programming and object-oriented
  programming are two of the most significant
  approaches to the design process.

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Program Design Program Design Tools

• Structure charts
• Program flowcharts
• Pseudocode
• Data modeling

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Program Design Control Structures

• Sequence
• Selection
• Iteration

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Program Design Good Program Design

• Be specific
• One-entry-point, one-exit-point rule
• No infinite loops
• Documentation during program design includes all
  the design specifications

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Program Coding

• Coding actual process of creating the program in
  a programming language.
• Programming language must be chosen.
• Coding standards should be adhered to.
• Make use of reusable code and data dictionaries.
• Translate coded programs into executable code.
• Documentation results in finished source code.

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Program Debugging and Testing

• Debugging process of making sure a program is
  free of errors.
• Preliminary bugging often finds syntax or logic
  errors.
• Testing can consist of alpha or beta testing.
• Documentation includes a copy of the finished
  program code, plus test data and results.

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Program Maintenance

• Program maintenance process of updating software
  so that it continues to be useful.
• A costly process, but can be used to extend the
  life of a program.
• Documentation consists of amended program package
  reflecting what problems occurred and what
  program changes were made.

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Tools for Facilitating Program Development

• Application generators
• Computer-aided software engineering
• Rapid application development

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Application Generators

• An application generator enables both programmers
  and end users to code new applications quickly.
• Macro languages
• Report generators
• Form generators
• Graphics generators
• Code generators

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Computer-Aided Software Engineering

• CASE tools automate one or more steps of
  applications software development.
• Features include
• Action-diagram editors
• Fourth-generation-language programming
• Code generators
• Reusable-code-management routines
• Active data dictionaries

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Rapid-Application Development

• Rapid application development (RAD) enables
  software development to take place during the
  entire program development process.
• RAD tools provide CASE-like assistance for
  developing user interfaces, preparing code for
  reuse, etc.

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What Is a Programming Language?
A programming language is a set of rules used to
write instructions to the computer.
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Categories of Programming Languages

• Low-level languages
• High-level languages
• Fourth-generation languages (4GLs)
• Natural and visual languages

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Popular Programming Languages

• FORTRAN
• COBOL
• Pascal

• BASIC and Visual Basic
• C, C, AND C
• Java

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Markup Languages

• Markup languages use symbols or tags to describe
  what a document should look like when displayed.
• HTML
• Dynamic HTML
• XML
• XHTML
• WML

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Scripting Languages

• Scripting languages are used to build program
  instructions into Web pages, usually to add
  dynamic content.
• JavaScript
• VBScript
• Perl

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Technology Tools and Modeling Languages

• Active X alternative to Java for creating
  interactive Web pages
• Extends object linking and embedding (OLE) to the
  Web
• Can be used to view common types of documents via
  Web pages, as well play special content
• VRML specification for displaying
  three-dimensional objects on the Web