This is my top 5 of best ways to improve your code base on many code reviews and some good practices

1. TOP 5 WAYS TO IMPROVE
YOUR CODE
Top 5 best ways to improve your code
Write once
read many.

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3. INTRODUCTION
Legacy code is
code without tests
 Michael Feather in
Working effectively
with legacy code
Without
maintenance, code
degrade rapidly
We must detect and
get rid of code
smell
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4. MY 5 IMPROVEMENTS
1. Simplify conditionals
2. Remove comments
3. Clarify contracts
4. Control scope
5. Flush dead code
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5. SIMPLIFY CONDITIONALS
WHY?
1
2
3
4
5




Reduce complexity
Improve readability
Improve maintainability
Improve Reusability
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6. SIMPLIFY CONDITIONALS
WHEN?
1
2
3
4
5





There is more than one conditions (and / or)
There is too many code in the body
Condition is based on type
There are nested conditions
There are many outcome from the same information (if /
elseif / switch case)
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7. SIMPLIFY CONDITIONALS
HOW?
1
2
3
4
5
 Refactor conditional statement







Decompose conditional
Consolidate conditional expression
Consolidate duplicate conditional fragments
Introduce null object
Flatten nested if
Don't use negative
Keep conditional statement lean
 Avoid conditional statement
 Replace conditional with polymorphism
 Replace conditional logic with strategy
 Replace conditional dispatcher with command
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8. 2
3
4
5
SIMPLIFY CONDITIONALS
1
DECOMPOSE CONDITIONAL
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9. 2
3
4
5
SIMPLIFY CONDITIONALS
1
CONSOLIDATE CONDITIONAL EXPRESSION
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10. 2
3
4
5
SIMPLIFY CONDITIONALS
1
CONSOLIDATE DUPLICATE CONDITIONAL
FRAGMENTS
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11. 2
3
4
5
SIMPLIFY CONDITIONALS
1
INTRODUCE NULL OBJECT
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12. 2
3
4
5
SIMPLIFY CONDITIONALS
1
FLATTEN NESTED IF
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13. 2
3
4
5
SIMPLIFY CONDITIONALS
1
DON'T USE NEGATIVE
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14. 2
3
4
5
SIMPLIFY CONDITIONALS
1
KEEP CONDITIONAL STATEMENT LEAN
 As much as possible, try to use only one
condition per if statement
 Use a method to combine many conditions
 Inverse if statement if most of the code is inside
the true branch
 Avoid double negation
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15. 2
3
4
5
SIMPLIFY CONDITIONALS
1
REPLACE CONDITIONAL WITH
POLYMORPHISM
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16. 2
3
4
5
SIMPLIFY CONDITIONALS
1
REPLACE CONDITIONAL LOGIC WITH
STRATEGY
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17. 2
3
4
5
SIMPLIFY CONDITIONALS
1
REPLACE CONDITIONAL DISPATCHER WITH
COMMAND
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18. 1
REMOVE COMMENTS
WHY?
2
3
4
 Improve readability
 Improve maintainability
 Avoid obsolete comments
5
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19. REMOVE COMMENTS
WHEN?
1
2
3
4
5
 Each time a comment add anything else than useful
information, intention, clarification, warning, todo or
amplification
 Comment for empty block of code
 Empty catch
 Describe code line by line
 Example:




//
//
//
//
Getting connection string from configuration
Opening connection
Retrieving data
Closing connection
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20. REMOVE COMMENTS
HOW?
1
2
3
4
5
 Replace comment with good naming
 Extract method
 Use meaningful words
 Write useful comments
 Respect standard naming (MSDN: Guidelines for names)




Properties
Enums
Events
Methods
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21. EXTRACT METHOD
2
3
4
5
REMOVE COMMENTS
1
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22. USE MEANINGFUL NAMES
2
3
4
5
REMOVE COMMENTS
1
 Use Intention-Revealing names

d  elapsedInDays
 Avoid disinformation

AccountList  Accounts
 Make meaningful distinction

moneyAmount vs money vs amount  InvoiceTotal
 Use pronounceable names

genymdhms  generationTimestamp
 Avoid mental mapping

a  account
 Class names  noun not verbs
 Method names  verbs
 Don't be cute. Use standard names

Destroy, kill, obliterate  Delete
 Solution Domain Names vs Problem Domain
Names
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23. PROPERTIES
2
3
4
5
REMOVE COMMENTS
1
 Use PascalCase naming
 Use noun or adjective
 Don't use names that might be confused with a
Get
 Prefix boolean with Can, Is, or Has
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24. ENUMS
2
3
4
5
REMOVE COMMENTS
1
 First element should be
default value
 Use PascalCasing naming
 Single value enum should
be singular
 Bit field enum should be
plural and has a Flag
attribute
 Bit field enum values must
be coherent (Read & Write
== ReadWrite)
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25. EVENTS
2
3
4
5
REMOVE COMMENTS
1
 Use PascalCase naming
 Use past to describe post -event and present
progressive for pre-event
 Provide a virtual method
 Provide a cancel behavior for a pre -event
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26. EVENTS
2
3
4
5
REMOVE COMMENTS
1
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27. METHODS
2
3
4
5
REMOVE COMMENTS
1
 Use verbs as method name
 ProcessPayment
 Explicitly express return type in method name
 CreateCustomer
 GetInvoice
 Use coherent naming (Get, Fetch or Retrieve but
not all for the same usage context)
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28. 1
CLARIFY CONTRACTS
WHY?
2
3
4
 Improve performance
 Improve readability
 Improve reusability
5
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29. CLARIFY CONTRACTS
QUAND?
1
2
3
4
5
 The is too many paramters (how many is too much?)
 A method has more than one responsability
 A method use out paramters
 Except for:
 TryPattern
 Service contracts
 You need a default value
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30. CLARIFY CONTRACTS
HOW?
1
2
3
4
5
 Reduce the number of paramters
 Introduce parameter object
 Create overload with less parameters
 Use default value
 Outputs
 Use complex return type
 Use out parameters only when necessary
 Maintain parameters order for overloads
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31. INTRODUCE PARAMETER OBJECT
2
3
4
5
CLARIFY CONTRACTS
1
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32. CREATE OVERLOAD WITH FEWER
PARAMETERS
2
3
4
5
CLARIFY CONTRACTS
1
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33. USE DEFAULT VALUE
2
3
4
5
CLARIFY CONTRACTS
1
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34. CONTROL SCOPE
WHY?
1
2
3
4
 Avoid side effects
 Improve reusability
 Improve maintainability
5
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35. CONTROL SCOPE
WHEN?
1
2
3
 A field is used only n a few methods
 Internal implementation is exposed by public members
4
5
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36. CONTROL SCOPE
HOW?
1
2
3
4
5
 Visibility
 protected
 private
 internal
 Responsibility
 Move a field inside a method
 Split class
 Move variable closer to usage
 Lifetime
 Create instances as needed
 Release reference as early as possible
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37. FLUSH DEAD CODE
WHY?
1
2
3
4
5





Because we must
Improve maintainability
Improve performance
Improve readability
100% test coverage
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38. 1
FLUSH DEAD CODE
WHEN?
2
3
4
 You know the code is dead
 You think the code is dead
 You want the code to be dead
5
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39. FLUSH DEAD CODE
HOW?
1
2
3
4
5
 Identify and remove the code
 Delete le code
 Compile
 Run unit tests
 What is dead code?
 Code in comments
 Code not covered by unit test
 Tools
 There are tools that delete any line of not covered by at least one
unit test
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40. REFERENCES
 Refactoring – Improving the design of existing code
 Auteur: Martin Fowler
 Edition: Addison Wesley
 ISBN: 978-0-201-48567-7
 Refactoring to patterns (Martin Fowler signature)
 Auteur: Joshua Kerievsky
 Edition: Adison Wesley
 ISBN: 978-0-321-21335-1
 Clean code – a handbook of agile software craftsmanship
 Auteur: Robert C. Martin
 Edition: Prentice Hall
 ISBN: 978-0-132-35088-4
 Working effectively with legacy code
 Auteur: Michael C. Feather
 Edition: Prentice Hall
 ISBN: 978-0-13-117705-5
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41. THE END
 Questions?
 Remember
Simplify
conditionals
Remove
comments
Clarify
contracts
Control
scope
Flush dead
code
 Eric De Carufel
 eric@decarufel.net
 http://blog.decarufel.net
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