System.Object being the base class

Question

This question may be usual for many, i tried for an hour to understand the things but getting no proper explanation.

MSDN says, System.Object is the ultimate

Answer 1

Class A inherits from System.Object. Class B inherits from class A, which inherits from System.Object

Answer 2

Correct, C# only allows single inheritence. The System.Object class is inherited implicitly by your Class A. So Class B is-a A, which is-a System.Object. This is taken care of by the compiler so you don't need to explicitly say that Class A : System.Object (though you can if you want).

Answer 3

Multiple inheritance means that e.g. class A inherits from both class B and class C directly, like this:

class A : B, C

That doesn't work in C#. Your example means that you inherit from a class which itself inherits from another, like this:

class A : object
{
}

class B : A
{
}

That is possible in C#.

Answer 4

You can't inherit two classes, but you can inherit a hierarchy of classes.

System.Object
    |
     \-- Class A {}
         |
          \-- Class B {}



public class ClassA
{
}

public class ClassB : ClassA
{
}

public class ClassC : ClassB
{
}

Answer 5

Look, you can only have one father. But your father also can have a father. Thus, you inherit some attributes from your grandfather. Dog class inherits from Mammals, which in turn inherits from Animal class, which in turn inherits from LivingThing class.

Answer 6

Multiple inheritance means inheriting from multiple classes into one class. Your example is valid, but you wouldn't be able to do the following:

Class B : A,C { --- }

A definition for multiple inheritance:

"Multiple inheritance is a feature of some object-oriented computer programming languages in which a class can inherit behaviors and features from more than one superclass."