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Code Complete 2:Code Complete 2:Realities of ModernRealities of Modern

Software ConstructionSoftware Construction

www.construx.comwww.construx.com

20042004 --20052005 Construx Software Builders, Inc.Construx Software Builders, Inc. All Rights Reserved. All Rights Reserved.

ConstruxConstruxDelivering Software Project SuccessDelivering Software Project Success

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R

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Really,Really

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DA VINCICODECOMPLETESteve McConnell

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T h i s T i m e

t s P e r s o n a l

T h i s T i m e

t s P e r s o n a l

T h i s T i m e

I t s P e r s o n a l

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consulting training software projects construx.com8

Code Complete MissionCode Complete Mission

Attempt in 1993 was to capture lasting Attempt in 1993 was to capture lastingknowledge of software constructionknowledge of software constructionIIve asserted for many years that 95% ofve asserted for many years that 95% of

the content of CC1 is still relevantthe content of CC1 is still relevantWas this true?Was this true?

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Overview of TalkOverview of Talk

The Worst Construction Ideas of the 1990sThe Worst Construction Ideas of the 1990sand 2000sand 2000s

A Decade of Advances in Software A Decade of Advances in Software

ConstructionConstructionTen Realities of Modern SoftwareTen Realities of Modern SoftwareConstructionConstruction

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The WorstThe WorstConstruction Ideas ofConstruction Ideas of

the 1990s and 2000sthe 1990s and 2000s

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Some of the WorstSome of the WorstConstruction Ideas of 1990sConstruction Ideas of 1990s

Code & fixCode & fix All design up front All design up front programmingprogrammingDesign for speculative requirementsDesign for speculative requirementsComponents will solve all ourComponents will solve all ourconstruction problemsconstruction problems

Automatic programming Automatic programmingUninformed use of the waterfall modelUninformed use of the waterfall modelCalling everythingCalling everything object orientedobject oriented

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Some of the WorstSome of the WorstConstruction Ideas of 2000sConstruction Ideas of 2000s

Code & fixCode & fix No design up frontNo design up front programmingprogrammingPlanning to refactor later Planning to refactor later Offshore outsourcing will solve all ourOffshore outsourcing will solve all ourconstruction problemsconstruction problems

Automatic programming Automatic programmingUninformed use of Extreme ProgrammingUninformed use of Extreme ProgrammingCalling everythingCalling everything agileagile

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Worst Ideas, 1990s vs. 2000sWorst Ideas, 1990s vs. 2000s1990s1990s

Code & fixCode & fix All design up front All design up front programmingprogrammingDesign for speculativeDesign for speculative

requirementsrequirementsComponents will solve allComponents will solve allour construction problemsour construction problems

Automatic programming Automatic programmingUninformed use of theUninformed use of thewaterfall modelwaterfall modelCalling everythingCalling everything objectobject

orientedoriented

2000s2000s

Code & fixCode & fix No design up frontNo design up front programmingprogrammingPlanning to refactor later Planning to refactor later

Offshore outsourcing willOffshore outsourcing willsolve all our problemssolve all our problems

Automatic programming Automatic programmingUninformed use ofUninformed use ofExtreme ProgrammingExtreme ProgrammingCalling everythingCalling everything agileagile

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A Decade of AdvancesA Decade of Advancesin Softwarein Software

ConstructionConstruction

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0. With the Theatrical Release0. With the Theatrical Releaseof Lord of the Ringsof Lord of the Rings

ALL companies can have servers named ALL companies can have servers namedGandalf and FrodoGandalf and Frodo

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2. Daily Build and Smoke Test2. Daily Build and Smoke Test

Institutionalizes incremental integrationInstitutionalizes incremental integrationMinimizes serious integration problemsMinimizes serious integration problemsthat used to be commonthat used to be common

Lots of other benefits, tooLots of other benefits, too

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3. Standard Libraries3. Standard Libraries

Good programmers have always usedGood programmers have always usedlibrarieslibrariesNow provided with languages (Java, C++,Now provided with languages (Java, C++,

.NET).NET)

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4. Visual Basic4. Visual Basic

Visual programming innovationVisual programming innovationThe first development environment toThe first development environment tomake widespread use of COTSmake widespread use of COTS

componentscomponentsOnly language to learnOnly language to learn Ada Ada ss syntaxsyntaxlessons (case statements, controllessons (case statements, control

statements, etc.)statements, etc.)Highly integrated environmentHighly integrated environment

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5. Open Source Software5. Open Source Software

Great aid to programmers duringGreat aid to programmers duringdevelopmentdevelopmentReduced barriers to making code availableReduced barriers to making code available

Opportunity to learn from available codeOpportunity to learn from available codeImproved ability toImproved ability to readread codecodeNiceNice communitycommunity of programmersof programmers

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6. The Web for Research6. The Web for Research

FAQsFAQsDiscussion groupsDiscussion groupsSearchabilitySearchability in generalin general

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7. Widespread Use of7. Widespread Use ofIncremental DevelopmentIncremental Development

Concepts were well known in 1990sConcepts were well known in 1990sPractice is well established in 2000sPractice is well established in 2000s

From CC1:From CC1:The wordThe word incrementalincremental has never achieved thehas never achieved thedesigner status ofdesigner status of structuredstructured oror objectobject --oriented,oriented, soso

no one has ever written a book onno one has ever written a book on incrementalincrementalsoftware engineering.software engineering. ThatThat s too bad because thes too bad because thecollection of techniques in such a book would becollection of techniques in such a book would beexceptionally potent.exceptionally potent.

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8. Test8. Test --First DevelopmentFirst Development

Shortens time to defect detectionShortens time to defect detectionIncreases personal disciplineIncreases personal disciplineComplements daily build & smoke testComplements daily build & smoke test

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9. Refactoring as a Discipline9. Refactoring as a Discipline

Provides a discipline for making changesProvides a discipline for making changesNot so good as a total design strategyNot so good as a total design strategy

Good example of incrementalismGood example of incrementalism

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10. Faster Computers10. Faster Computers

Compare CC1 performance benchmarks toCompare CC1 performance benchmarks toCC2 benchmarksCC2 benchmarksImplications for optimizationImplications for optimization

Implications for programming languagesImplications for programming languagesImplications for developmentImplications for development

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Ten Realities ofTen Realities ofModern SoftwareModern Software

ConstructionConstruction

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--11 -- ConstructionConstruction is ais a

Legitimate TopicLegitimate Topic

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SoftwareSoftware ConstructionConstruction Used to Look Like ThisUsed to Look Like This

SoftwareConcept

SystemTesting

Arch it ecturalDesign

Requirements Analys is

DetailedDesign

Coding andDebugging

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SoftwareSoftware ConstructionConstruction Now Looks Like ThisNow Looks Like This

DetailedDesign

Integration

UnitTesting

IntegrationTesting

RequirementsDevelopment

ProblemDefinition

Software Archi tecture

SystemTesting

CorrectiveMaintenance

ConstructionPlanning

Coding andDebugging

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Distinction Between ActivitiesDistinction Between Activitiesand Phasesand Phases

Activity != Phase Activity != PhaseTalking aboutTalking about ConstructionConstruction as anas anactivity does not imply a distinct phaseactivity does not imply a distinct phase

Differentiating between kinds of activitiesDifferentiating between kinds of activitiesis extremely helpfulis extremely helpful

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--22 --Individual Variation IsIndividual Variation Is

SignificantSignificant

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Where do Variations Exist?Where do Variations Exist?

Researchers have found variations ranging fromResearchers have found variations ranging from10x to 28x in:10x to 28x in:Coding speedCoding speedDebugging speedDebugging speed

DefectDefect --finding speedfinding speedPercentage of defects foundPercentage of defects foundBadBad --fix injection ratefix injection rate

Design qualityDesign quality Amount of code generated from a design Amount of code generated from a designEtc.Etc.

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Key Skills of an ExpertKey Skills of an ExpertProgrammer Programmer

DesigningDesigningFlushing out errors and ambiguities inFlushing out errors and ambiguities inrequirementsrequirementsCoding (naming, formatting, commenting)Coding (naming, formatting, commenting)

Reading & reviewing codeReading & reviewing codeIntegrationIntegrationDebuggingDebugging

Unit testingUnit testingTeamworkTeamworkUsing tools for all of the aboveUsing tools for all of the above

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Why Personal DisciplineWhy Personal DisciplineMattersMatters

Being realistic about predicting the futureBeing realist ic about predicting the future Areas where discipline matters Areas where discipline matters

RefactoringRefactoringPrototypingPrototypingOptimizationOptimizationMinimalMinimal --complexity designs specificallycomplexity designs specificallyManaging complexity generallyManaging complexity generally

EndpointsEndpoints Discipline and CourageDiscipline and CourageHumphrey on PSPHumphrey on PSPBeck on Extreme ProgrammingBeck on Extreme Programming

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--44 --A Focus on SimplicityA Focus on SimplicityWorks Better than aWorks Better than a

Focus on ComplexityFocus on Complexity

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Simplicity vs. ComplexitySimplicity vs. Complexity

Why do projects fail?Why do projects fail?Focus on readFocus on read --time convenience, nottime convenience, notwritewrite --time conveniencetime convenience

YAGNI and design for speculativeYAGNI and design for speculativerequirementsrequirements

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--55 --DefectDefect --Cost IncreaseCost Increase

is Alive and Wellis Alive and Well

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Defect Cost IncreaseDefect Cost Increase

Requirements

Architecture

Construction

System testRequirements Architecture Construction Post-Release

AverageCost to

Correct

Activity in which aDefect IsIntroduced

Activity in Which a Defect Is Detected

Fix Here Dont Waitto Fix Here

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Decades of Research SupportDecades of Research SupportDefectDefect --Cost IncreaseCost Increase

Fagan, Michael E. 1976.Fagan, Michael E. 1976. Design and Code Inspections to Reduce Errors in ProgramDesign and Code Inspections to Reduce Errors in ProgramDevelopment.Development. IBM Systems JournalIBM Systems Journal 15, no. 3: 18215, no. 3: 182 211.211.Humphrey, Watts S., Terry R. Snyder, and Ronald R. Willis. 1991.Humphrey, Watts S., Terry R. Snyder, and Ronald R. Willis. 1991. Software ProcessSoftware ProcessImprovement at Hughes Aircraft.Improvement at Hughes Aircraft. IEEE SoftwareIEEE Software 8, no. 4 (July): 118, no. 4 (July): 11 23.23.Leffingwell, Dean, 1997.Leffingwell, Dean, 1997. Calculating the Return on Investment from More EffectiveCalculating the Return on Investment from More EffectiveRequirements Management,Requirements Management, American Programmer American Programmer , 10(4):13, 10(4):13 --16.16.

Willis, Ron R., et al, 1998.Willis, Ron R., et al, 1998. Hughes AircraftHughes Aircraft s Widespread Deployment of a Continuouslys Widespread Deployment of a ContinuouslyImproving Software Process,Improving Software Process, Software Engineering Institute/Carnegie Mellon University,Software Engineering Institute/Carnegie Mellon University,CMU/SEICMU/SEI --9898 --TRTR --006, May 1998.006, May 1998.Grady, Robert B. 1999.Grady, Robert B. 1999. An Economic Release Decision Model: Insights into Software An Economic Release Decision Model: Insights into SoftwareProject Management.Project Management. InIn Proceedings of the Applications of Software MeasurementProceedings of the Applications of Software MeasurementConferenceConference , 227, 227 --239. Orange Park, FL: Software Quality Engineering.239. Orange Park, FL: Software Quality Engineering.

Shull, et al, 2002.Shull, et al, 2002. What We Have Learned About Fighting Defects,What We Have Learned About Fighting Defects, Proceedings, MetricsProceedings, Metrics20022002 . IEEE; pp. 249. IEEE; pp. 249 --258.258.Boehm, Barry and Richard Turner, 2004.Boehm, Barry and Richard Turner, 2004. Balancing Agility and Discipline: A Guide for theBalancing Agility and Discipline: A Guide for thePerplexedPerplexed , Boston, Mass.: Addison Wesley, 2004., Boston, Mass.: Addison Wesley, 2004.

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--66 --Design Is ImportantDesign Is Important

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Design AdviceDesign Advice What hasWhat hasChanged in 10 Years?Changed in 10 Years?

In 1990s, design pundits wanted to dotIn 1990s, design pundits wanted to doteveryevery ii and cross everyand cross every tt before writingbefore writingany codeany codeIn 2000s, design pundits say BDUF?In 2000s, design pundits say BDUF?YAGNI!YAGNI!There are lots of valid points on theThere are lots of valid points on the nonodesigndesign all designall design continuumcontinuumThe only 2 points guaranteed to be wrongThe only 2 points guaranteed to be wrongare the two that have been advocated!are the two that have been advocated!

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General Point: Extremes areGeneral Point: Extremes areUsually Not ProductiveUsually Not Productive

All design up front vs. no design up front All design up front vs. no design up frontEntirely planned vs. entirely improvisedEntirely planned vs. entirely improvisedPure iterative vs. straight sequentialPure iterative vs. straight sequential

All structure vs. all creative All structure vs. all creativeDocument everything vs. documentDocument everything vs. documentnothingnothing

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--77 --Technology WavesTechnology Waves

Affect ConstructionAffect ConstructionPracticesPractices

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--88 --IncrementalIncremental

Approaches Work BestApproaches Work Best

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Perspective on IncrementalismPerspective on Incrementalism

The pure waterfall model is not at all incrementalThe pure waterfall model is not at all incrementalor iterativeor iterative which is why it hasnwhich is why it hasn t worked veryt worked verywellwellSpiral development is highly incremental andSpiral development is highly incremental and

iterative, which is part of why it does work welliterative, which is part of why it does work well All projects will experience iteration at some All projects will experience iteration at somepointpoint

Think aboutThink about wherewhere andand whenwhen in your project youin your project youwill get your incrementalismwill get your incrementalism cheaply, orcheaply, orexpensively?expensively?

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--99 --The Toolbox MetaphorThe Toolbox Metaphor

Continues to beContinues to beIlluminatingIlluminating

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Toolbox Metaphor Toolbox Metaphor

WhatWhat s best? Agile? XP? Scrum? DSDM? CMM?s best? Agile? XP? Scrum? DSDM? CMM?Toolbox explains thereToolbox explains there s no one right tool fors no one right tool forevery jobevery jobDifferent industry segments will have differentDifferent industry segments will have differenttools and even different toolboxestools and even different toolboxesWhatWhat s in the Software Engineering Toolbox?s in the Software Engineering Toolbox?

Best practicesBest practices

Lifecycle modelsLifecycle modelsTemplates, checklists , patterns, examplesTemplates, checklists, patterns, examplesSoftware toolsSoftware tools

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--1010 --SoftwareSoftware s Essentials Essential

Tensions RemainTensions Remain

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SoftwareSoftware s Essential Tensionss Essential Tensions

SoftwareSoftware s essential tensions have remaineds essential tensions have remainedunchanged for years:unchanged for years:Rigid plans vs. ImprovisationRigid plans vs. ImprovisationPlanning vs. Fortune TellingPlanning vs. Fortune Telling

Creativi ty vs. StructureCreativi ty vs. StructureDiscipline vs. Flexibili tyDiscipline vs. Flexibili tyQuantitative vs. QualitativeQuantitative vs. QualitativeProcess vs. ProductProcess vs. Product

Optimizing vs.Optimizing vs. SatisficingSatisficing

Balance wavers, but basic tensions are constantsBalance wavers, but basic tensions are constants

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TALKCOMPLETE

Steve McConnell

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TrainingSoftware ProjectsCoaching & Consulting

[email protected]

www.construx.com

ConstruxConstruxDelivering Software Project SuccessDelivering Software Project Success

200607 McConnell

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