C++ Interview Questions and Answers

What is C++?

C++ is an object-oriented programming language created by Bjarne Stroustrup in 1985.

What are the differences between C and C++?

C++ is a superset of C language.

C is a procedural programming language, but C++ supports both procedural and Object Oriented programming.

In C++ can use access modifier to restrict access of member function and variable to outside class and user, but in C we can’t do that.

What are the differences between C++ and Java?

C++ has pointers, but Java does not support pointer.
Java is platform-independent, but C++ is not.
Java has garbage collection, but C++ does not.
C++ used complier but Java uses interpreter.
C++ support operator overloading and multiple inheritance but Java not support both.

Explain is Object Oriented Programming (OOP)?

Object-oriented programming is a techniques for managing enormous complexity, achieving reuse of software components, and coupling data with the procedures that work on that data as a single "object"--a self-contained entity.

The basic concepts of Object Oriented Programming are given below:
Class and Object: Class is a template and implementation of entities whereas Object is variable and representation of class.
Encapsulation and data hiding: the binding of data and methods together called Encapsulation, where hide the data or direct access from outside known as data hiding.
Inheritance: Inheritance is concept of reusability and can used this to inherit the property of one class into another class.
Polymorphism: Poly means many, and morph means form. Polymorphism refers to the same name taking many forms or can perform different task depend on context.

What is a class in C++?

Class is a user-defined data type. It can consist of any combination of the variable types and also other class types.
The variables in the class are referred to as the member variables or data members and the functions in the class referred to as member Functions or methods of the class.

What is an object?

An object is an individual instance of a class and also called a class variable.
It can access the class members and functions by using the dot (.) operator.

Define the private, public and protected in C++?

Private, Public and protected and are three access specifier in C++.

Private: All members of a class data and methods are private by default. Private members can be accessed only within methods of the class itself.
Public: Public members can be accessed through any object of the class.
Protected: data members and member functions are only available to derived classes.

Explain constructor?

Constructors is special member function of class with the same name as the class and it used to create and initialize Object.
The constructor can take parameters as needed, but it cannot have a return value--not even void.
We can do Overloading of Constructor.

Explain destructor?

Destructors always has the name of the class, preceded by a tilde (~) and clean up allocated memory. Destructors take no arguments and have no return value.
We cannot Overload of destructor.

What is Default Constructors and Destructors?

If we don't declare a constructor or a destructor manually, the compiler makes one for you. The default constructor and destructor take no arguments and do nothing.

What is a copy constructor?

A copy constructor is the constructor which copies the exact values of one object's member variables into another object.
Copy constructors take one parameter, which a reference to an object of the same class.

Explain the static variable and member function?

Static variables and member functions belonging to the class rather than to the object. Normal member data is one per object, but static members are one per class and they can be called without having an object of that class.

 

What is a friend function?

A function which is not a member of the class but still can access all private and protected member data and functions of the class.
Function can declare friend by using the keyword friend and then the full specification of the function.

 

What is Inheritance?

Inheritance is the process of acquiring the properties of the existing class into the new class.
A class which adds new functionality to an existing class is said to derive from that original class. The original class is said to be the new class's base class.

 

What is function overriding?

A derived class creates a function with the same return type and signature (function name, as well as the number and type of its Parameters) as a member function of the base class, but with a new implementation, it is said to be overriding that method.

 

What is polymorphism?

Polymorphism is the ability to treat many objects of differing but related types without regard to their differences.

 

Latest Updates

General Knowledge of India

Which of the following dance forms was introduced by the great Vaishnava saint and reformer Mahapurusha Sankaradeva ?

Which of the following is the only classical dance of india having links with Muslim culture and represents a unique synthesis of Hindu and Muslim genius in art ?

Time and Distance

Starting from the same point at the same time, Ruhan and Yuvan had to reach the same destination. While Ruhan drove at 45 km/hr, Yuvan was slower by 5 km/hr. If Yuvan arrived at the destination an hour after Ruhan did, the distance covered by each, in Kilometres, was ?

Simple Interest

A sum of money was invested at a certain rate of simple interest for 4 years. Had the sum been invested at a rate 3% higher than the actual rate, the interest earned would have been 720 Rs more. Find the sum initially invested?

Ratio and Proportion

A bag contains red, blue and black balls. The ratio of red to blue balls is 3 : 5. The ratio of black to red balls is 3 : 4. What is the ratio of blue to black balls?

Profit and Loss

Selling a pack of incense sticks for 136 Rs resulted in a loss of 15%. To make a profit of 10%, the selling price should be ?

Percentage

23% of a bucket full of diluted milk was water. If the quantity of pure milk in the bucket was 15.4 liter, then the capacity of the bucket was ?

Average

The average of the marks obtained by three girls in a test was twice the average of the marks obtained by eight boys in that test. If the total marks obtained by all these examinees was 168, find the average marks each of the girls obtained ?

Pipes and Cistern

44 pipes can fill a large water tank in 27 hours. How many hours it take for 66 pipes to fill four such tanks ?

HCF and LCM

A natural number, when divided by 3, 4, 5, 6, and 7 respectively, leaves corresponding remainder of 2, 3, 4, 5 and 6. What is the smallest of all such numbers fulfilling the above condition ?

Coding-Decoding

If in a certain code language, PRINT is written as 34825 and TRUE is written as 5479. Then, how will TENURE be written in that language?

Order Sequence

Arrange the given words from smallest to biggest-
1.Jug
2.Mug
3.Bucket
4.Drum
5.Cup

Statement and Conclusion

Statements
All socks are shoes
Some shoes are black

Conclusions
I. Some shoes are socks.
II. No scoks is black

Numbers

The difference between the place value of 4 and 2 in the number 833749502 is ?

Analogy

GIKM : HJLN :: PRTV : .........?

Order Sequence

In a row of girls, Nanda is eighth from the left and Chanda is nineteenth from right. When Nanda and Chanda interchange their positions, Chanda becomes twnty-third form right. How many girls are there in the row?

Analogy

Summer: Day :: Winter : ........?

Bird:Winges :: Fish:........?