25 C# OOPs Interview Questions Every Programmer Should Read

This post is for programmers gearing for their first C# OOPs interview. C# is the most popular object-oriented programming language used by millions of developers. So every interviewer rates your C# programming skills based on how well-versed you are in OOPs concepts.

Hence, we picked 25 key OOPs questions for C# programmers. It is a quick way to brush up programming skills and knowledge of C# OOPs concepts. We’ve clubbed both the theoretical and coding questions together so that you can focus on coding as well as theory.

If you also like to explore additional C# topics for interview prep, then do visit the C# interview section to check hundreds of programming questions and answers.

However, before you proceed, please have a look at the below questions/areas that you must also prepare for securing a C# programming job.

1. What are types in C# – Value & Reference types?
2. What are access modifiers in C#?
3. What are the basic OOPs concepts in C#?
    a. class (Abstract, partial, sealed, static etc.)
    b. enum
    c. struct
    d. interface
4. What do you know about Partial types and Partial methods?
5. What is the use of ‘typeof’ keyword in C#?
6. How do you call the multiple constructors of a class with a single object creation?
7. How to debug a running C# program?
8. How do you implement an interface and call its methods?
9. What is the use of “REF” & “OUT” keyword in C#?
10. How will you use “params” & “dynamic” in method parameters?

So we leave you here to ponder the answers and drill the areas mentioned above.

Now, it’s time that you put your C# programming skills to test as the 25 C# questions are waiting for you next.

25 C# OOPs Interview Questions for Programmers.

25 C# OOPs Interview Questions for Programmers

25 C# OOPs Interview Questions.

Q-1. Which of the following represents the process of defining two or more methods within the same class having the same name but different parameters list?
a) Method overloading
b) Method overriding
c) Encapsulation
d) None of the mentioned

Click here to see the answer.
a)

 

Q-2. Which of the following are applicable for overloading?
a) Constructors
b) Methods
c) Both a & b
d) None of the mentioned

Click here to see the answer.
c)

 

Q-3. What will be the output of the following code snippet?

a) Compile time error
b) 25
    6
c) 216
    5
d) 216
    25

Click here to see the answer.
d)

 

Q-4. Which of the following unary operators support overloading?
1. true
2. false
3. +
4. new
5. is

a) 1, 2, 3
b) 3, 4, 5
c) 3 only
d) 5 only

Click here to see the answer.
a)

 

Q-5. Which of the following statements is correct?
a) On using the new keyword as a modifier, it explicitly hides a member inherited from a base class.
b) Operator overloading works differently for structures and classes.
c) It is not necessary that all operator overloads are static methods of the class.
d) The cast operator can be successfully overloaded.

Click here to see the answer.
a)

 

Q-6. Which of the following keywords can be used to overload user-defined types by defining static member functions?
a) op
b) opoverload
c) operator
d) operatoroverload
e) udoperator

Click here to see the answer.
c)

 

Q-7. Which of the following statements are correct?
a) You cannot overload the conditional logical operators.
b) If you overload the binary operator then the corresponding assignment operator, if any, must be explicitly overloaded.
c) We can use the default equality operator in its “overload” implementation.
d) A public or “nested public”, reference type does not overload the equality operator.
e) The array indexing operator can be overloaded.

Click here to see the answer.
a)

 

Q-8. Which of the following modifier applies when a virtual method is redefined by a derived class?
a) overloads
b) override
c) overridable
d) virtual
e) base

Click here to see the answer.
b)

 

Q-9. Which of the following keyword should be prefixed to a member of the base class to allow overriding in the derived class?
a) overload
b) override
c) new
d) virtual
e) base

Click here to see the answer.
d)

 

Q-10. Which of the following members of the class allow declaring them as virtual?
a) Methods
b) Properties
c) Events
d) Fields
e) Static fields

Click here to see the answer.
a) b) c)

 

Q-11. What will be the output of the following code snippet?

a) 4, 3.5
b) 8, 0
c) 7.5, 8
d) 8, 7

Click here to see the answer.
d)

 

Q-12. What will be the output of the following code snippet?

a) Printing func1
    20
b) Printing func1
    Printing func2
    20
c) Printing func1
    20
    Printing func2
d) Compile time error

Click here to see the answer.
a)

 

Q-13. What will be the output of the following code snippet?

a) 190, 26.78f
b) 0, 26.78f
c) 190, 26
d) 190, 0

Click here to see the answer.
c)

 

Q-14. What will be the output of the following code snippet?

a) 1 1 1
b) 0 0 0
c) 25 100000 12.34
d) -25 -100000 -12.34

Click here to see the answer.
c)

 

Q-15. Which of the following represents the process where a method in a subclass has same name & type signature as a method in its superclass?
a) Method overloading
b) Method overriding
c) Method hiding
d) None of the mentioned

Click here to see the answer.
b)

 

Q-16. Which of the following modifiers can be used to prevent Method overriding?
a) Static
b) Constant
c) Sealed
d) final

Click here to see the answer.
c)

 

Q-17. What will be the output of the following code snippet?

a) 0
b) 2
c) 1
d) Compile time error

Click here to see the answer.
b)

 

Q-18. Which of the following keywords to be assigned to a base class method so as to override that method in the subclass?
a) virtual
b) abstract
c) Static
d) Override

Click here to see the answer.
a) b) d)

 

Q-19. What will be the output of the following code snippet?

a) Compile Time Error
b) BaseClass
    DerivedClass
c) BaseClass
    BaseClass
d) DerivedClass
     BaseClass

Click here to see the answer.
c)

 

Q-20. What will be the output of the following code snippet?

a) Compile Time Error
b) BaseClass
    DerivedClass
c) BaseClass
    BaseClass
d) DerivedClass
     BaseClass

Click here to see the answer.
b)

 

Q-21. What will be the output of the following code snippet?

a) Compile time Error
b) Runtime Error
c) BaseClass
d) DerivedClass
    

Click here to see the answer.
d)

 

Q-22. What will be the output of the following code snippet?

a) Compile time Error
b) Derived2Class
c) BaseClass
d) DerivedClass
    

Click here to see the answer.
d)

 

Q-23. What will be the output of the following code snippet?

a) Compile time Error
b)  DerivedClass
     Derived2Class
c) DerivedClass
    DerivedClass
d) DerivedClass
    BaseClass
    

Click here to see the answer.
d)

 

Q-24. Which of the following are correct for methods of a class that becomes applicable to method overloading?
a) Type of arguments may differ
b) Return type of methods need not be same
c) Number of arguments may vary
d) Names of methods to be different
e) Variation in the order of arguments.

Click here to see the answer.
a) c) e)

 

Q-25. What will be the output of the following code snippet?

a) Compile time error
b) Runtime error
c) Method Overriding
d) Program runs successfully and nothing is printed

Click here to see the answer.
c)

Summary – 25 C# OOPs Interview Questions and Answers.

We wish the above questions set would help during your C# OOPs interview. And we’ll keep coming up with more posts to improve your programming and logical skills.

If you like to share any feedback or your experience, then use the comment box to reach to us.

Keep Learning,

TechBeamers.

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