Coding Standards & Best Practices for iOS/C#

Coding Standards and Best
Programming Practices

Compiled by : Asim R. Siddiqui

"Where there are two bugs, there is likely to be a
third.“

“Don't patch bad code - rewrite it."

"Don't stop with your first draft."

Quotations

Software Maintenance
Less Bugs
Teamwork
Team switching
Cost

Why Have Coding
Standards?

Introduction
Anybody can write code. With a few months of programming experience, you can write
'working applications'. Making it work is easy, but doing it the right way requires more
work, than just making it work.

Believe it, majority of the programmers write 'working code', but not ‘good code'. Writing
'good code' is an art and you must learn and practice it.

Everyone may have different definitions for the term ‘good code’. In my definition, the
following are the characteristics of good code.

Reliable
Maintainable
Efficient

Purpose of coding standards
and best practices
To develop reliable and maintainable applications, you must follow
coding standards and best practices.

The naming conventions, coding standards and best practices described
in this document are compiled from our own experience and by
referring to various Microsoft and non Microsoft guidelines.

There are several standards exists in the programming industry. None of
them are wrong or bad and you may follow any of them. What is more
important is, selecting one standard approach and ensuring that
everyone is following it.

How to follow the standards
across the team

If you have a team of different skills and tastes, you are going to have a
tough time convincing everyone to follow the same standards. The
best approach is to have a team meeting and developing your own
standards document. You may use this document as a template to
prepare your own document.

After you start the development, you must schedule code review meetings
to ensure that everyone is following the rules. 3 types of code reviews are
recommended:

Peer review – another team member review the code to ensure that the code
follows the coding standards and meets requirements. Every file in the
project must go through this process.

Architect review – the architect of the team must review the core modules of
the project to ensure that they adhere to the design and there is no “big”
mistakes that can affect the project in the long run.

Group review – randomly select one or more files and conduct a group review
once in a week.

Naming Conventions and
Standards
Note :
The terms Pascal Casing and Camel Casing are used throughout this
document.
Pascal Casing - First character of all words are Upper Case and other
characters are lower case.
Example: BackColor
Camel Casing - First character of all words, except the first word are Upper
Case and other characters are lower case.
Example: backColor

1. Use Pascal casing for Class names

public class HelloWorld
{
...
}

2. Use Pascal casing for Method names

void SayHello(string name)
{
...
}

3. Use Camel casing for variables and method parameters

int totalCount = 0;
void SayHello(string name)
{
string fullMessage = "Hello " + name;
...
}

6. Use Meaningful, descriptive words to name variables. Do not use abbreviations.

Good: Not Good:

string address string nam
int salary string addr
int sal

7. Do not use single character variable names like i, n, s etc. Use names like
index, temp
One exception in this case would be variables used for iterations in loops:

for ( int i = 0; i < count; i++ )
{
...
}

If the variable is used only as a counter for iteration and is not used anywhere
else in the loop, many people still like to use a single char variable (i)
instead of inventing a different suitable name.

8. Do not use underscores (_) for local variable names.

9. All member variables must be prefixed with underscore (_) so that they can
be identified from other local variables.

10.Do not use variable names that resemble keywords.

11. Prefix boolean variables, properties and methods with “is” or similar
prefixes.

Ex: private bool _isFinished

12.Namespace names should follow the standard pattern

<company name>.<product name>.<top level module>.<bottom level module>

Control Prefix
Label lbl
TextBox txt

DataGrid dtg
Button btn
ImageButton imb
Hyperlink hlk
DropDownList ddl

ListBox lst

DataList dtl

Repeater rep

Checkbox chk

CheckBoxList cbl

RadioButton rdo

RadioButtonList rbl

Image img

Panel pnl

PlaceHolder phd

Table tbl

Validators val

14. File name should match with class name.

Indentation and Spacing
1. Use TAB for indentation. Do not use SPACES. Define the Tab size as 4.

2. Comments should be in the same level as the code (use the same level of
indentation).

Good:

// Format a message and display

DateTime currentTime = DateTime.Now;
string message = fullMessage + ", the time is : " +
currentTime.ToShortTimeString();
MessageBox.Show ( message );

Not Good:

// Format a message and display

3.Curly braces ( {} ) should be in the same level as the code outside the braces.

4. Use one blank line to separate logical groups of code.

Good:
bool SayHello ( string name )
{

string message = fullMessage + ", the time is : " + currentTime.ToShortTimeString();


if ( ... )
{
// Do something
// ...

return false;
}

return true;
}

Not Good:

bool SayHello (string name)
{
if ( ... )
{
// Do something
// ...
return false;
}
return true;
}

5. There should be one and only one single blank line between each method
inside the class.

6. The curly braces should be on a separate line and not in the same line as
if, for etc.

Good:
if ( ... )
{
// Do something
}

Not Good:

if ( ... ) {
// Do something
}

7. Use a single space before and after each operator and brackets.

Good:
if ( showResult == true )
{
for ( int i = 0; i < 10; i++ )
{
//
}
}

Not Good:

if(showResult==true)
{
for(int i= 0;i<10;i++)
{
//
}
}

Good Programming
Practices
1. Avoid writing very long methods. A method should typically have 1~25 lines of
code. If a method has more than 25 lines of code, you must consider re
factoring into separate methods.

2. Method name should tell what it does. Do not use mis-leading names. If the
method name is obvious, there is no need of documentation explaining what
the method does.

Good:
void SavePhoneNumber ( string phoneNumber )
{
// Save the phone number.
}

Not Good:

// This method will save the phone number.
void SaveDetails ( string phoneNumber )
{
// Save the phone number.
}

3. A method should do only 'one job'. Do not combine more than one job in a
single method, even if those jobs are very small.

Good:
// Save the address.
SaveAddress ( address );

// Send an email to the supervisor to inform that the address is updated.
SendEmail ( address, email );

void SaveAddress ( string address )
{
// ...
}

void SendEmail ( string address, string email )
{
// Send an email to inform the supervisor that the address is changed.
// ...
}

Not Good:

// Save address and send an email to the supervisor to inform that
// the address is updated.
SaveAddress ( address, email );

void SaveAddress ( string address, string email )
{
// Job 1.
// ...

// Job 2.
// Send an email to inform the supervisor that the address is changed.
// ...
}

7. Do not hardcode strings. Use resource files.

8. Convert strings to lowercase or upper case before comparing. This will ensure
the string will match even if the string being compared has a different case.

if ( name.ToLower() == “john” )
{
//…
}

9. Use String.Empty instead of “”

Good:

If ( name == String.Empty )
{
// do something
}

Not Good:

If ( name == “” )
{
// do something
}

10. Avoid using member variables. Declare local variables wherever necessary and
pass it to other methods instead of sharing a member variable between methods. If
you share a member variable between methods, it will be difficult to track which
method changed the value and when.

11. Use enum wherever required. Do not use numbers or strings to indicate discrete
values.

Good:
enum MailType
{
Html,
PlainText,
Attachment
}

void SendMail (string message, MailType mailType)
{
switch ( mailType )
{
case MailType.Html:
// Do something
break;
case MailType.PlainText:
// Do something
break;
case MailType.Attachment:
// Do something
break;
default:
// Do something
break;
}
}

Not Good:

void SendMail (string message, string mailType)
{
switch ( mailType )
{
case "Html":
// Do something
break;
case "PlainText":
// Do something
break;
case "Attachment":
// Do something
break;
default:
// Do something
break;
}
}

12. Do not make the member variables public or protected. Keep them private and
expose public/protected Properties.

13.The event handler should not contain the code to perform the required action.
Rather call another method from the event handler.

14. Do not programmatically click a button to execute the same action you have
written in the button click event. Rather, call the same method which is called by the
button click event handler.

15. Never hardcode a path or drive name in code. Get the application path
programmatically and use relative path.

16. Never assume that your code will run from drive "C:". You may never know,
some users may run it from network or from a "Z:".

17. In the application start up, do some kind of "self check" and ensure all required
files and dependancies are available in the expected locations. Check for database
connection in start up, if required. Give a friendly message to the user in case of
any problems.

18. If the required configuration file is not found, application should be able to
create one with default values.

19. If a wrong value found in the configuration file, application should throw an error or
give a message and also should tell the user what are the correct values.

20. Error messages should help the user to solve the problem. Never give error
messages like "Error in Application", "There is an error" etc. Instead give specific
messages like "Failed to update database. Please make sure the login id and password
are correct."

21. When displaying error messages, in addition to telling what is wrong, the message
should also tell what should the user do to solve the problem. Instead of message like
"Failed to update database.", suggest what should the user do: "Failed to update
database. Please make sure the login id and password are correct."

22. Show short and friendly message to the user. But log the actual error with all
possible information. This will help a lot in diagnosing problems.

23. Do not have more than one class in a single file.

24. Have your own templates for each of the file types in Visual Studio. You can
include your company name, copy right information etc in the template. You can view or
edit the Visual Studio file templates in the folder C:Program FilesMicrosoft
Visual Studio 8Common7IDEItemTemplatesCacheCSharp1033. (This
folder has the templates for C#, but you can easily find the corresponding folders or any
http://shwetketu.blogspot.com
other language)

25. Avoid having very large files. If a single file has more than 1000 lines of code, it
is a good candidate for refactoring. Split them logically into two or more classes.

27. Avoid passing too many parameters to a method. If you have more than 4~5
parameters, it is a good candidate to define a class or structure.

28. If you have a method returning a collection, return an empty collection instead
of null, if you have no data to return. For example, if you have a method returning
an ArrayList, always return a valid ArrayList. If you have no items to return, then
return a valid ArrayList with 0 items. This will make it easy for the calling application
to just check for the “count” rather than doing an additional check for “null”.

30. Logically organize all your files within appropriate folders. Use 2 level folder
hierarchies. You can have up to 10 folders in the root folder and each folder can
have up to 5 sub folders. If you have too many folders than cannot be
accommodated with the above mentioned 2 level hierarchy, you may need re
factoring into multiple assemblies.

31. Make sure you have a good logging class which can be configured to log
errors, warning or traces. If you configure to log errors, it should only log errors.

32. If you are opening database connections, sockets, file stream etc, always
close them in the finally block. This will ensure that even if an exception
occurs after opening the connection, it will be safely closed in the finally
block.

33. Declare variables as close as possible to where it is first used. Use one
variable declaration per line.

Comments
1. Good and meaningful comments make code more maintainable. However,

2. Do not write comments for every line of code and every variable declared.

3. Use // or /// for comments. Avoid using /* … */

4. Write comments wherever required. But good readable code will require very less
comments. If all variables and method names are meaningful, that would make the
code very readable and will not need many comments.

5. Do not write comments if the code is easily understandable without comment. The
drawback of having lot of comments is, if you change the code and forget to
change the comment, it will lead to more confusion.

6. Fewer lines of comments will make the code more elegant. But if the code is not
clean/readable and there are less comments, that is worse.

7. If you have to use some complex or weird logic for any reason, document it very
well with sufficient comments.

6. Do not write try-catch in all your methods. Use it only if there is a possibility
that a specific exception may occur and it cannot be prevented by any other
means. For example, if you want to insert a record if it does not already exists in
database, you should try to select record using the key

Coding Standards & Best Practices for iOS/C#

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