Pair programming

PAIR PROGRAMMING
BY SANDEEP P R

ABOUT ME
 STARTED MY CAREER IN 2003 IN .NET ESPECIALLY ASP.NET
TECHNOLOGIES
 WORKING WITH INDECOMM FOR NEARLY 4 YEARS
 ASP.NET, JAVASCRIPT (OOPS), EXTJS, ASP.NET MVC, ASP.NET
WEBAPI ETC.
 FAN OF DESIGN PATTERNS
 BDD (BEHAVIOR DRIVEN DEVELOPMENT) AND TDD (TEST
DRIVEN DEVELOPMENT)
 AGILE (SRUM AND EXTREME PROGRAMMING [XP])
 OTHER

AGENDA
 WHAT IS PAIR PROGRAMMING?
 PARTICIPANTS IN PAIR PROGRAMMING
 PAIRING VARIATIONS
 MYTHS
 GUIDELINES
 ADVANTAGES
 PROBLEMS
 TIT BITS
 QUESTIONS

WHO IS A PROGRAMMER?
“LONELY MACHO
WARRIORS, BATTLING
AGAINST A SEA OF BITS
AND BYTES.”Professor Matthias Felleisen

WHEN THINGS GO RIGHT?
WE ARE CHILDISHLY
DELIGHTED WITH WHAT
WE HAVE CREATED

WHEN THINGS GO WRONG?
“BANG-YOUR-HEAD-AGAINST-
THE-WALL”

“A TECHNIQUE THAT CAN RADICALLY
INCREASE THE NUMBER OF TIME THINGS
GO RIGHT AND DECREASE THE NUMBER
OF TIMES THINGS GO WRONG”

PAIR PROGRAMMING
WIKI DEFINITION
PAIR PROGRAMMING IS AN AGILE
SOFTWARE DEVELOPMENT TECHNIQUE
IN WHICH TWO PROGRAMMERS WORK
TOGETHER AT ONE WORKSTATION.
ONE, THE DRIVER, WRITES CODE WHILE
THE OTHER, THE OBSERVER, REVIEWS
EACH LINE OF CODE AS IT IS TYPED IN.
THE TWO PROGRAMMERS SWITCH
ROLES FREQUENTLY.

WHAT PAIR PROGRAMMING MEANS?
 PAIR DESIGN
 PAIR DEBUGGING
 PAIR TESTING
 PAIR CODING

DRIVER
 FOCUSES ON THE CODE
AT HAND
 SYNTAX
 SEMANTICS
 ALGORITHM

OBSERVER
 POINTER OR NAVIGATOR
 KEEPS AN EYE ON TACTICAL AND STRATEGIC ERRORS
 TACTICAL ERROR: TYPOS, SYNTACTICAL ERRORS, CALLING THE
WRONG METHOD ETC
 STRATEGIC ERROR: IMPLEMENTATION IS MEETING THE GOAL OR
NOT
 SANITY TESTING THE CODE
 THINKING THROUGH PROBLEMS
 WHERE TO GO NEXT
 KEEP THE DRIVER ON COURSE

PAIRING VARIATIONS
 EXPERT-EXPERT
 EXPERT-NOVICE
 NOVICE-NOVICE

EXPERT-EXPERT PAIRING
 TO SOLVE COMPLEX PROBLEMS
 CAN GIVE GREAT RESULTS
 LESS TIME SPEND ON EXPLAINING
THINGS
 NO NEW WAYS TO SOLVE THE
PROBLEMS
 UNLIKELY TO QUESTION ESTABLISHED
PRACTICES
 EXPERTS HAVE BIG EGO, “DO IT MY WAY

EXPERT-NOVICE
 FOR MENTORING A NOVICE
 GETTING EASY JOB DONE
 CAN HAVE NEW SOLUTION TO A
PROBLEM
 NEW PEOPLE CAN HELP OUT
ALMOST IMMEDIATELY
 EXPERT HAS TO TAKE OFF “I
KNOW EVERYTHING” MASK
 CREATE CONDUCIVE
ENVIRONMENT

NOVICE-NOVICE
 MOSTLY HAPPENS IN
COLLEGES
 MENTOR HAS BE ASSIGNED
 EASY WAY TO LEARN THINGS
 PAIRS ARE MORE LIKELY TO ASK
QUESTION THAN INDIVIDUAL

MYTHS
 IT WILL DOUBLE THE WORKLOAD WITH TWO DOING THE WORK ONE
CAN DO
 I’LL NEVER GET TO WORK ALONE. I COULDN’T STAND THAT!
 IT WILL WORK WELL ONLY WITH THE RIGHT PARTNER
 PAIR PROGRAMMING IS GOOD FOR TRAINING. BUT, ONCE YOU
KNOW WHAT YOU’RE DOING, IT IS A WASTE OF TIME
 I’LL NEVER GET CREDIT FOR DOING ANYTHING. I’LL HAVE TO
SHARE ALL THE RECOGNITION WITH MY PARTNER
 THE ONLY TIME I EVER GET ANY REAL WORK DONE IS WHEN I’M
ALONE. NOW, I’LL NEVER GET ANYTHING
DONE! PAIR PROGRAMMING WOULD DRIVE ME CRAZY

GUIDELINES
 MIN OF 17INCH MONITOR AND
COMFORTABLE SEATING
 TALK A LOT
 NO POINTING ON THE SCREEN WITH
FINGER (NAVIGATOR)
 PAIR ROTATION
 GIVE THE DRIVER NANO SECONDS TO FIND
AND CORRECT HIS/HER OWN MISTAKES
 INTRA AND INTERPAIR COMMUNICATION
 DEVELOPMENT ENVIRONMENT

GUIDELINES CONTD…
 MAKE USE OF TDD
 PRACTICE ACTIVE LISTENING
 NOISE CONSIDERATION
 IF YOU PARTNER IS NOT LISTENING, JUST WALK AWAY
 IF YOU DON’T UNDERSTAND WHAT YOUR PARTNER IS DOING,
THEN STOP AND ASK. STILL YOU DON’T UNDERSTAND , ASK
AGAIN, ASK AGAIN ASK AGAIN….
 TAKE ENOUGH SHOWER; EAT LOTS OF BREATH MINTS

ADVANTAGES
 INSTANT CODE REVIEW
 KNOWLEDGE SHARE
 REDUCES THE TRAINING COST
 EXCELLENT TOOL TO BREAK COMMUNICATION BARRIERS
BETWEEN TEAMMATES
With Pair Programming Without Pair Programming
Assimilation Time (work days) 18 40
Mentoring Time (%) 26 36
Training Effort (work days) 15 37

PROBLEMS, PROBLEMS AND LOT MORE PROBLEMS
 DEPENDENCY
 SCHEDULING
 THE EVER POPULAR EXPERT
 COLOCATION
 NOISE AND FACILITY CONSIDERATION
 CONCENTRATION
 DISAGREEMENT
 OVERCONFIDENCE
 RUSHING
 SKILL IMBALANCE
 SIMPLY NOT FOR EVERYONE

TIT BITS
MICROSOFT RESEARCH BY ANDREW BEGEL & NACHIAPPAN
NAGAPPAN

MICROSOFT RESEARCH BY ANDREW BEGEL & NACHIAPPAN NAGAPPAN
CONT…

ALISTAIR COCKBURN & LAURIE WILLIAMS
THE COSTS AND BENEFITS OF PAIR PROGRAMMING

ALISTAIR COCKBURN & LAURIE WILLIAMS

CONCLUSION
• SUPPORT FROM TEAM/MENTOR/LEADER/COACH AND OF
COURSE FROM THE MANGER
• 20YEARS OF DATA FOR BENEFITS OF REVIEW
• PROGRAMMERS AVOID REVIEW LIKE PLAGUE
• PROGRAMMERS ARE STRONG BELIEVERS THAT THEY CAN
ACHIEVE MORE BY GOING SOLO
• COLLECT AND DISSEMINATE INFORMATION/METRICS TO THE
TEAM
• MANAGEMENT BY WALKING AROUND

RESEARCH LINKS
• HTTP://RESEARCH.MICROSOFT.COM/PUBS/75108/ESEM-BEGEL-
2008.PDF
• HTTP://WWW.CS.POMONA.EDU/CLASSES/CS121/SUPP/WILLIAMS_PR
PGM.PDF
• HTTP://WWW.SOBERIT.HUT.FI/~JVANHANE/PUBS/LICTHESIS_VANHAN
EN.PDF
• HTTP://CITESEERX.IST.PSU.EDU/VIEWDOC/DOWNLOAD?DOI=10.1.1.2
58.7427&REP=REP1&TYPE=PDF
• HTTP://AGILE.VTT.FI/DOCS/PUBLICATIONS/2005/2005_MULTIPLE_CAS
E_STUDY_PAIR_PROGRAMMING.PDF

WAYS TO REACH ME
• SANDEEP.R@ACCELRYS.COM
• SANDEEP.R@INDECOMM.NET
• HTTPS://WWW.LINKEDIN.COM/IN/SANDEEPPR
• HTTPS://TWITTER.COM/SNDPPR

Pair programming

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