Editing Class variable (section)

{{short description|Variable defined in a class whose objects all possess the same copy}}

In [[class-based]], [[object-oriented programming]], a '''class variable'''  is a [[Variable (programming)|variable]] defined in a [[Class (computer programming)|class]] of which a single copy exists, regardless of how many [[Instance (computer science)|instance]]s of the class exist.<ref name=TheJavaTurotialVariables>{{cite web|url=http://download.oracle.com/javase/tutorial/java/nutsandbolts/variables.html|title=The Java Tutorial, Variables |accessdate=2010-10-21}}</ref><ref name=TheJavaTutorialUnderstandingInstanceAndClassMembers>{{cite web|url=http://download.oracle.com/javase/tutorial/java/javaOO/classvars.html|title=The Java Tutorial, Understanding Instance and Class Members|accessdate=2010-10-21}}</ref><ref name=ThePythonLanguageReferenceCompoundStatements>{{cite web|url=https://docs.python.org/reference/compound_stmts.html#class-definitions|title=The Python Language Reference, Compound Statements|accessdate=2010-10-21}}</ref><ref name=ObjectiveCRuntimeReference>{{cite web|url=https://developer.apple.com/documentation/objectivec/objective_c_runtime|title= Objective-C Runtime Reference |website=Apple Developer|accessdate=1 April 2018}}</ref><ref name=ClassVariablesinCSharp>{{cite web|title=Class Variables in C#|url=https://syntaxdb.com/ref/csharp/class-var|website=Syntaxdb|accessdate=1 April 2018}}</ref>

A class variable is not an [[instance variable]]. It is a special type of [[Class (computer science)#Structure|class attribute]] (or class property, [[Field (computer science)|field]], or data member). The same dichotomy between ''instance'' and ''class'' members applies to [[method (computer science)|method]]s ("member functions") as well; a class may have both [[instance method]]s and [[class method]]s.