How to create an instance of an object in c#

Question

Greeting for the day!

I have a question in my mind and looking for answer from some days. If my understanding is correct then only diff between Instance and object is :-

instance means just creating a reference(copy) .

object :means when memory location is associated with the object( is a runtime entity of the class) by using the new operator

Now i want to know how to create an instance of an object. Please give explanation with sample code

Any help will be appreciated. Thanks

Answer 1

By your explanation it's not called an instance, but a reference of an object. An instance of a class is called an object. I think your question is: "What is the difference of an object and a reference variable?" I'll try to explain it with some examples:

Foo f;

I just declared a reference variable. This is not an object but only a reference that refers to an object.

f = new Foo();

Now I created a new object and assigned it to the f reference variable so every time I do something to f I refer to the Foo object. Like when I call f.Name = "MyFoo"; I refer to the foo object.

Foo otherFoo;

Now I declare another reference variable.

otherFoo = f;

What we have here now is having ONE object in the memory but TWO reference variables refering to the same object.

f.IsFoo = true;
bool isotherFooFoo = otherFoo.IsFoo;

This last line will return true because we changed the IsFoo property to true and f and otherFoo reffer to the same object.

I hope that explains you everything. :)

Answer 2

You don't create "an instance of an object", you create an instance of a class (or struct). An object is an instance of a class.

If you do:

Foo f = new Foo();

You create an instance of the Foo class.

Answer 3

In C# 9.0 there is a new way to initialize a class by Target-typed new expressions.

You can initialize the class like this:

Foo f = new();

Note, f is a reference to the class Foo.