Program%20Development%20and%20Programming%20Languages

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Chapter 13

• Program Development and Programming Languages

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Overview

• This chapter covers
• The program development life cycle (PDLC)
• Tools that can facilitate program development
• Programming languages

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The Program Development Life Cycle (PDLC)
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Problem Analysis

• Purpose Review the specifications developed
  during system design and develop program
  specifications.
• Usually performed by systems analyst and
  programmer.
• Documentation Program specifications (what is
  does, timetable, programming language to be used,
  etc.)

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Program Design

• Purpose To determine the algorithms to be used
  with the final program.
• Approaches to program design
• Structured programming
• Structures the program
• Object-oriented programming (OOP)
• Groups program components
• Aspect-oriented programming (AOP)
• Re-uses program components

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Program Design, Contd.

• Program design tools
• Structure charts
• Program flowcharts
• Pseudocode
• Data modeling

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Program Design, Contd.

• Control structurespatterns that control when and
  how the instructions in a computer program are
  performed.
• Sequence
• Selection (if-then-else, case)
• Repetition (do-while, do-until)

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Program Design, Contd.

• Good program design
• Be specific.
• One-entry-point, one-exit-point rule.
• No infinite loops or logic errors.
• Documentation Design specifications (expressed
  using flowcharts, pseudocode, structure charts,
  data models, etc.).

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Program Coding

• Codingthe process of writing the actual
  programming steps using a programming language.
• Factors involved when choosing a programming
  language
• Suitability
• Integration
• Standards

• Programmer availability
• Portability
• Development speed

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Program Coding, Contd.

• Coding standardslist of rules designed to
  standardize programming styles.

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Program Coding, Contd.

• Reusable code
• Data dictionary
• Translating coded programs into executable code
• Compilers
• Interpreters
• Assemblers
• Documentation Documented, executable source
  code.

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Program Debugging and Testing

• Debuggingthe process of making sure a program is
  free of errors.
• Preliminary debugging
• Syntax errors (typos, wrong syntax, etc.).
• Logic errors (wrong formulas, wrong relational
  operators, etc.).
• Dummy print statements can help locate errors.

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Program Debugging and Testing

• Testing
• Alpha testing (inside organization)
• Beta testing (outside testers)
• Documentation Completed program package.

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Program Maintenance

• Program maintenancethe process of updating
  software so that it continues to be useful.
• Software updates
• Software revisions
• Made easier by good coding standards, data
  dictionaries, reusable code, etc.
• Documentation Amended program package.

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Tools for Facilitating Program Development

• Application generators
• Macro recorders
• Report and form generators
• Code generators
• Computer-aided software engineering (CASE)
• Software-asset management tools
• Rapid application development (RAD)

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Programming Languages

• Programming languagea set of rules used to write
  instructions to the computer.
• Categories of programming languages
• Low-level languages (machine and assembly
  language).
• High-level languages (BASIC, COBOL, C, etc.).
• Very-high-level (fourth-generation languages).
• Natural and visual languages.

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Popular Programming Languages

• FORTRANthe oldest high-level programming
  language designed for scientific and
  mathematical applications.

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Popular Programming Languages, Contd.

• COBOLdesigned for business transaction
  processing.

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Popular Programming Languages, Contd.

• Pascaldesigned to teach structured programming
  useful for math and science applications.

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Popular Programming Languages, Contd.

• BASICan easy-to-learn beginners programming
  language.
• Visual Basican object-oriented,
  fourth-generation version of BASIC.

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Popular Programming Languages, Contd.

• C, C, Cversions of the highly efficient C
  programming language C and C are
  object-oriented.

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Popular Programming Languages, Contd.

• Javaobject-oriented programming language
  commonly used for Web applications.
• Platform independenceJava programs can run on
  any platform that supports the Java Virtual
  Machine.
• Java appletsconcise stand-alone Java
  applications ready to be inserted into Web pages.
• Class files
• Parameters

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Popular Programming Languages, Contd.

• Other high-level languages
• Ada
• APL
• LISP
• Logo

• PL/1
• Prolog
• RPG
• SmallTalk

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Summary

• The program development life cycle (PDLC)
• Good program design
• Basic control structures
• Coding, debugging, maintaining, and documenting
  programs
• Tools that facilitate the program development
  process
• Common programming languages