.Net Interview Questions - OOP

What is Object Oriented Programming (OOP)?
Object-oriented programming (OOP) is a programming language model organized around objects. At this poing you may have a question in your mind, what is an object? its simple, an object can be anything which has some attributes and hehaviour. For example, hope now you are infront of a computer monitor, the monitor itself is an object, it has a lot of attributes like Make, Size, Type etc...

In OOP we use classes and objects to represent our data and logic. For example consider the following C# example.

    public class Monitor
    {
        public string Make
        {
            set;
            get;
        }

        public int Height
        {
            set;
            get;
        }
 
 
        //etc......
   }

The above class defines a structure of the computer monitor. An object of this class can represent a computer monitor.
OOP Concepts

1. Data Abstraction : The act of representing essential features without showing the back ground details.


2. Data Encapsulation: The wrapping up of data together into a single unit.


3. Inheritance: The act of inheriting properties of an object into another.


4. Polymorphism: The ability of a data to behave in multiple forms.

Possible questions about OOP concepts from a .NET stand point are:

1. What is Data Abstraction? ans: see above definition


2. What is Encapsulation? ans: see above definition


3. What is inheritance? ans: see above definition


4. What is Polymorphism? ans: see above definition


5. Does .Net support multiple inheritance? ans: no


6. Example for polymorphism? ans:function overloading, overriding and operator overloading


7. Real world example for data abstraction? ans: when we press the start switch of a car or bike will get started, we might not need to know the internal process. we gave an input and we got an outcome.


8. What is a class and an object? ans: class is a blueprint for creating objects. An object is an instance of a class and it have the properties and behaviours defined in the class.