Transcript Understanding Computers, 10/e, Chapter 13

Chapter 13
Program Development and
Programming Languages
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Overview

This chapter covers:
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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
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Purpose: Review the specifications developed during
system design and develop program specifications.
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Usually performed by systems analyst and
programmer.
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Documentation: Program specifications (what is
does, timetable, programming language to be used,
etc.)
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Program Design
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Purpose: To determine the algorithms to be used with the final
program.
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Approaches to program design:
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Structured programming
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Object-oriented programming (OOP)
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Structures the program
Groups program components
Aspect-oriented programming (AOP)
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Re-uses program components
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Program Design, Cont’d.
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Program design tools:
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Structure charts
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Program flowcharts
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Pseudocode
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Data modeling
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Program Design, Cont’d.
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Control structures—patterns that control when and
how the instructions in a computer program are
performed.
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Sequence
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Selection (if-then-else, case)
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Repetition (do-while, do-until)
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Program Design, Cont’d.
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Good program design
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Be specific.
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One-entry-point, one-exit-point rule.
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No infinite loops or logic errors.
Documentation: Design specifications (expressed
using flowcharts, pseudocode, structure charts, data
models, etc.).
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Program Coding
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Coding—the process of writing the actual
programming steps using a programming language.
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Factors involved when choosing a programming
language:
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Suitability
Integration
Standards
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Programmer availability
Portability
Development speed
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Program Coding, Cont’d.
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Coding standards—list of rules designed to
standardize programming styles.
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Program Coding, Cont’d.
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Reusable code
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Data dictionary
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Translating coded programs into executable code
 Compilers
 Interpreters
 Assemblers
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Documentation: Documented, executable source
code.
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Program Debugging and Testing
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Debugging—the process of making sure a program
is free of errors.
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Preliminary debugging
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Syntax errors (typos, wrong syntax, etc.).
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Logic errors (wrong formulas, wrong relational
operators, etc.).
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Dummy print statements can help locate errors.
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Program Debugging and Testing
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Testing
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Alpha testing (inside organization)
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Beta testing (outside testers)
Documentation: Completed program package.
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Program Maintenance
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Program maintenance—the process of updating
software so that it continues to be useful.
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Software updates
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Software revisions
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Made easier by good coding standards, data
dictionaries, reusable code, etc.
Documentation: Amended program package.
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Tools for Facilitating Program
Development
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Application generators:
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Macro recorders
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Report and form generators
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Code generators
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Computer-aided software engineering (CASE)
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Software-asset management tools
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Rapid application development (RAD)
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Programming Languages
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Programming language—a set of rules used to
write instructions to the computer.
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Categories of programming languages:
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Low-level languages (machine and assembly
language).
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High-level languages (BASIC, COBOL, C++, etc.).
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Very-high-level (fourth-generation languages).
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Natural and visual languages.
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Popular Programming Languages
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FORTRAN—the oldest
high-level programming
language; designed for
scientific and
mathematical
applications.
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Popular Programming Languages,
Cont’d.
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COBOL—designed for business transaction
processing.
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Popular Programming Languages,
Cont’d.
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Pascal—designed to teach structured programming;
useful for math and science applications.
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Popular Programming Languages,
Cont’d.
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BASIC—an easy-to-learn beginner’s programming
language.
Visual Basic—
an object-oriented,
fourth-generation
version of BASIC.
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Popular Programming Languages,
Cont’d.
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C, C++, C#—versions of the highly efficient C
programming language; C++ and C# are objectoriented.
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Popular Programming Languages,
Cont’d.
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Java—object-oriented programming language
commonly used for Web applications.
 Platform independence—Java programs can run
on any platform that supports the Java Virtual
Machine.
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Java applets—concise stand-alone Java
applications ready to be inserted into Web pages.
 Class files
 Parameters
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Popular Programming Languages,
Cont’d.
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Other high-level languages:
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Ada
APL
LISP
Logo
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PL/1
Prolog
RPG
SmallTalk
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Summary
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The program development life cycle (PDLC)
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Good program design
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Basic control structures
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Coding, debugging, maintaining, and documenting
programs
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Tools that facilitate the program development process
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Common programming languages
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