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In object-oriented computer programming, a null object is an object with no referenced value or with defined neutral (null) behavior.The null object design pattern, which describes the uses of such objects and their behavior (or lack thereof), was first published as "Void Value" [1] and later in the Pattern Languages of Program Design book series as "Null Object".
Java does not have uninitialized variables. Fields of classes and objects that do not have an explicit initializer and elements of arrays are automatically initialized with the default value for their type (false for boolean, 0 for all numerical types, null for all reference types). [4]
In C++, a constructor of a class/struct can have an initializer list within the definition but prior to the constructor body. It is important to note that when you use an initialization list, the values are not assigned to the variable. They are initialized. In the below example, 0 is initialized into re and im. Example:
In computer programming, unspecified behavior is behavior that may vary on different implementations of a programming language. [clarification needed] A program can be said to contain unspecified behavior when its source code may produce an executable that exhibits different behavior when compiled on a different compiler, or on the same compiler with different settings, or indeed in different ...
Languages with an explicit return statement create the possibility of multiple return statements in the same function. Whether or not that is a good thing is controversial. Strong adherents of structured programming make sure each function has a single entry and a single exit (SESE).
this, self, and Me are keywords used in some computer programming languages to refer to the object, class, or other entity which the currently running code is a part of. The entity referred to thus depends on the execution context (such as which object has its method called). Different programming languages use these keywords in slightly ...
Classes can have multiple superclasses, a list of slots (member variables in C++/Java parlance) and a special metaclass. Slots can be allocated by class (all instances of a class share the slot) or by instance. Each slot has a name and the value of a slot can be accessed by that name using the function slot-value. Additionally special generic ...
In the Perl programming language, autovivification is the automatic creation of new arrays and hashes as required every time an undefined value is dereferenced. Perl autovivification allows a programmer to refer to a structured variable, and arbitrary sub-elements of that structured variable, without expressly declaring the existence of the ...