Coding Style Guide•Topic 3 of 5•~5 min

Naming Conventions

Variable Named 'x' Causes Three-Day Debugging Session; Developer Claims 'It Made Sense at the Time'

Illustration of a naming convention museum with exhibits showing good vs bad variable names

Dear Marilyn: I named my variable 'temp' because it's temporary. Now I have 47 variables named 'temp' and I can't tell them apart. Help.

— Temporarily Confused in Tampa

Dear Temporarily: You have discovered, through painful experience, the First Law of Naming: A name should describe what something IS, not what it ISN'T. "Temporary" describes what it isn't (permanent). What IS it? A customer? An order? A database connection? Name it that.

The C# Naming Conventions

Element	Convention	Example
Classes	PascalCase	CustomerService
Interfaces	IPascalCase	IOrderRepository
Methods	PascalCase	CalculateTotal()
Properties	PascalCase	FirstName
Local Variables	camelCase	orderTotal
Private Fields	_camelCase	_customerRepository
Constants	PascalCase	MaxRetryCount
Parameters	camelCase	customerId

Names to Avoid

Never Use:

temp, tmp, data
x, y, z (except in math)
foo, bar, baz
thing, stuff, item
myVariable, theObject

Instead Use:

pendingOrder, cachedResult
xCoordinate, yPosition
testCustomer, mockRepository
orderLineItem, configurationSetting
currentUser, selectedProduct

Quick Check

What is the correct naming convention for a private field in C#?