Difference between Instance and Object in C# and ..

Question

Halo Frnds What is the difference between Instance and Object in C# and class A { public virtual void get() { Console.WriteLine(Hello); } } class B:A { public override void get() { Console.WriteLine(Fine); } } Ist Method A e = new B(); e.get(); IInd Method B e = new B(); e.get(); Difference between in Ist Method and IInd Method of intializing the object of the the Class A

swati · Answer

there is a minor difference between an object and an instance for example; class1 obj; hereobj is an instance of class1 which takes up the stack memory class1 obj=new class1(); in this case obj is an object of the class and takes up the heap memory.

Vulpes · Answer

With respect swati you're confusing instances of a class with variables of the same class type. In this line: class1 obj; 'obj' is of course a variable of type class1 which (assuming it's a local variable) is currently undefined. However storage for it (4 bytes on a 32-bit system or 8 bytes on a 64-bit system) has already been reserved for it within the method's stack frame. In this line: class1 obj=new class1(); 'obj' is again a local variable of type class1 which has a slot on the method's stack. However an instance (or object) of class1 has been created on the heap and a reference (or pointer) to it has been assigned to the variable. Consequently the variable's slot contains a reference to that instance - it doesn't contain the instance itself.

Munesh Sharma · Answer

A blueprint for a house design is like a class description. All the houses built from that blueprint are objects of that class. A given house is an instance.

Reza Taibur · Answer

It depends. If you are talking about object its an alias of the class Object. But if you are asking for about object of a class its an instance of the class in the heap. Class c = new Class(); Here new Class(); makes creates a new instance(kind of like a virtual copy) of the class Class And c is a reference variable ( pointer) of the class Class. Now you use pointer c to edit the object you created there. And the whole this Class c = new Class(); is also called an instance more like a complete one where you have pointer to edit them. Class definition is a blueprint of a house. Class objects are the house that were made using that blue print. Also objects are created in the heap while reference variables are in stack. And the objects that dont have pointers (reference ) pointing at them gets destroyed by the garbage collector. I am self teaching my self to code once I remember in a video the guy explained this like this : objects with out pointer are like orphans in the heap they are just waiting there for garbage collector to run over and destroy them :(.

Sadaqat Hussain · Answer

No such difference between object and instance. This pholymophic behavior where u r assigning the reference of B to A.

Alan · Answer

Well first of all there's no difference between an instance and an object of a particular class - they mean the same thing. In the first piece of code an object of type B is created but is then assigned to a variable 'e' of type A. This is allowed because B is derived from A. When e.get() is invoked it's actually B's get() method which is called. This is because the method is declared as 'virtual' and so the runtime type of the object held by 'e' (namely B) determines which class's version of the get() method is called. In the second piece of code an object of type B is created and is then assigned to a variable 'e' of type B. When e.get() is called B's version of get() is still called because B is the runtime type of 'e'.