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Constructors often have the same name as the declaring class. They have the task of initializing the object's data members and of establishing the invariant of the class, failing if the invariant is invalid. A properly written constructor leaves the resulting object in a valid state. Immutable objects must be initialized in a constructor.
In C#, apart from the distinction between value types and reference types, there is also a separate concept called reference variables. [3] A reference variable, once declared and bound, behaves as an alias of the original variable, but it can also be rebounded to another variable by using the reference assignment operator = ref. The variable ...
A resurrected object may be treated the same as other objects, or may be treated specially. In many languages, notably C#, Java, and Python (from Python 3.4), objects are only finalized once, to avoid the possibility of an object being repeatedly resurrected or even being indestructible; in C# objects with finalizers by default are only finalized once, but can be re-registered for finalization.
Instance variables or attributes – data that belongs to individual objects; every object has its own copy of each one. All 4 variables mentioned above (first_name, position etc) are instance variables. Member variables – refers to both the class and instance variables that are defined by a particular class.
In many contexts, including C++, C# and Java, an object is created via special syntax like new typename(). In C++, that provides manual memory management, an object is destroyed via the delete keyword. In C# and Java, with no explicit destruction syntax, the garbage collector destroys unused objects automatically and non-deterministically.
The rules on pre- and postconditions are identical to those introduced by Bertrand Meyer in his 1988 book Object-Oriented Software Construction.Both Meyer, and later Pierre America, who was the first to use the term behavioral subtyping, gave proof-theoretic definitions of some behavioral subtyping notions, but their definitions did not take into account aliasing that may occur in programming ...
In this example of a simple class representing a student with only the name stored, one can see the variable name is private, i.e. only visible from the Student class, and the "setter" and "getter" are public, namely the "getName()" and "setName(name)" methods.
The object methods include access to the object state (via an implicit or explicit parameter that references the object) whereas class methods do not. If the language supports inheritance , a class can be defined based on another class with all of its state and behavior plus additional state and behavior that further specializes the class.