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Top 50 Mostly Asked C++ Interview
Questions and Answers
C++ Interview Questions and Answers: An Overview
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C++ Interview Questions and Answers for Freshers
1. What are the Advantages of C++?
Object-Oriented Programming: Supports classes and objects, enabling better organization of
code and data encapsulation.
Efficiency: Allows low-level memory manipulation, resulting in faster execution and efficient use
of system resources.

Syntax:
Paradigm:
Function
Overloading:
Data Handling:
The 4 data types in C++, are
1. Primitive Datatype(basic datatype). Example- char, short, int, float, long, double, bool, etc.
2. Derived datatype. Example- array, pointer, etc.
3. Enumeration. Example- enum
4. User-defined data types. Example- structure, class, etc.
C
Procedural
language focused on functions
and structured programming.
Simpler syntax with a limited set
of keywords.
C++
The hybrid language supports both
programming
procedural and object-oriented
programming paradigms.
Extended syntax with
additional
keywords for classes, objects, and other
OOP features.
Relies on structures and functions
for data manipulation.
Supports classes and objects, allowing
data encapsulation and abstraction.
Allows defining multiple functions with
the same name but different parameters.
Does
overloading.
not support function
Standard is another name for "std," or it can be seen as a namespace. The compiler is instructed to
add all objects under the std namespace and import them into the global namespace by using the
command "using namespace std." Because of the global namespace instillation, we may use "cout"
and "cin" instead of "std::_operator_."
Inheritance and Polymorphism: Supports inheritance, allowing the creation of new classes
based on existing ones, and polymorphism, enables dynamic method binding.
Standard Template Library (STL): Provides a collection of useful classes and functions,
enhancing code reuse and productivity.
Flexibility: Allows both high-level and low-level programming, catering to a wide range of
applications.
3. Define ‘std'.
4. What is the difference between C and C++?
2. What are the different Data Types present in C++?

Operator
Overloading:
Standard
Template Library
(STL):
Exception
Handling:
Does
overloading.
not support operator Permits defining custom behaviors for
operators in user-defined classes.
Provides STL, a powerful library offering
generic classes and functions for various
data structures and algorithms. Supports
try-catch blocks for robust
exception handling.
Lacks
containers,
iterators.
built-in support for
and
algorithms,
Relies
conditional statements for error
handling.
on error codes and
Instance: An object is an instance of a class, representing a specific entity.
Attributes: Objects store data defined in the class's attributes.
Methods: Objects can invoke the methods defined in the class, performing operations specific to
that object's type.
Blueprint: A class is a blueprint or a template for creating objects.
Data and Functions:The encapsulation of data (attributes) and functions (methods) that operate
on the data.
Abstraction: Provides a way to represent real-world entities with properties, behaviours, and
expressions.
A variable becomes an alias of an existing variable when it is described as a reference. To put it
simply, a referred variable is a named variable that is another variable that already exists, with
the understanding that any changes made to the reference variable would also affect the
previously existing variable. A reference variable has a '&' before it.
5. What are References in C++?
6. What are Class and Object in C++?
Class:
Object:
Syntax:
int DNT = 10;
// reference variable
int& ref = DNT;

behaviours.
Example: If "Car" is a class, an object could be a specific car with its unique attributes and
Value Passing: When a function is called by value, the actual value of the variable is passed to the
function.
Copy of Data: A copy of the actual parameter's value is created in the function's parameter
variable.
Changes are Local: Changes made to the parameter inside the function are local to the function
and do not affect the original variable outside the function.
Efficiency: Slower for large data structures as it involves copying the entire data.
Syntax: void function(int x) { ... }
Reference Passing: When a function is called by reference, the memory address of the actual
variable is passed to the function.
Direct Access: The function directly operates on the original data, not on a copy.
Changes are Global: Modifications inside the function affect the original variable outside the
function.
Efficiency: Faster and memory-efficient as it avoids creating a copy of the data.
Syntax: void function(int &x) { ... }
7. What do you mean by Call by Value and Call by Reference in C++?
Call by Value:
Call by Reference:

Usage:
Pointers:
Default
Member
Access:
Methods:
Access Control:
Inheritance:
References:
Watch this Video - Difference Between CallBy Value & CallBy Reference
Cannot have member functions until
C++11 standard.
Can have member functions for
encapsulating
manipulation.
behavior and data
Struct
Members are public by default.
Class
Members are private by default.
Does not support member access
control keywords like private and
protected. Primarily used for grouping
data
members and creating simple data
structures with minimal methods.
Members are public unless explicitly
specified otherwise
Supports member access control,
enabling private, protected, and public
inheritance. Used for creating complex
data
structures with methods,
encapsulation, and data hiding.
Members are private unless explicitly
specified otherwise.
In C++, a token is a fundamental unit of source code, representing individual elements recognized by
the compiler during lexical analysis:
Identifiers: Names for variables, functions, classes, etc.
Keywords: Reserved words with specific meanings, e.g., if, else, int.
Literals: Constants like numbers (42, 3.14) or strings ("hello").
Operators: Symbols for mathematical (+, -) or logical (&&, ||) operations.
Comments: Single-line (//) or multi-line (/* */) comments ignored by the compiler.
Whitespace: Spaces, tabs, and newlines separating tokens but generally not stored for further
processing.
8. Define token in C++
9. What is the difference between struct and class in C++?
10. What is the difference between Reference and Pointer in C++?

Watch this Video - Pointers in C++
Pointers store the memory address of a
variable.
Defined using * symbol, e.g., int *ptr.
References are aliases for existing variables.
Defined using & symbol during declaration, e.g.,
int &ref = var.
Cannot be NULL; must be initialized to a variable.
This can be NULL or reassigned to point to
different addresses.
Pointers can be reassigned to point to different
variables or addresses.
Requires * operator to access the value stored
at the address.
This cannot be reassigned to refer to a different
variable after initialization.
No need for an operator; accessed like a regular
variable.
Operator overloading in C++ allows defining custom behaviors for operators when used with user-
defined classes or data types. It enables objects of a class to behave like built-in types, allowing
programmers to provide their implementation of operators such as +, -, *, etc., tailored to specific
class instances.
11. What is Operator Overloading in C++?
Example in C++ Compiler
#include using namespace std; class
Complex { private: float real;
float imag;
public:
Complex() : real(0), imag(0) {}
Complex operator + (const Complex& obj) {
Complex temp;
temp.real = real + obj.real;
temp.imag = imag + obj.imag;
return temp;

Explanation
Run Code >>
In this code, the Complex class represents a complex number with real and imaginary parts. The +
operator is overloaded inside the class to add two complex numbers. The input() function is used to
input complex numbers, and the display() function is used to display the result. When you run the
program, it will prompt you to enter the real and imaginary parts of two complex numbers and then
display the sum.
return 0;
}
result = num1 + num2;
result.display();
} void input() { cout << "Enter real part: "; cin >> real;
cout << "Enter imaginary part: ";
cin >> imag;
}
void display() { if (imag < 0) { cout << "Sum = " << real
<< " - " << -imag << "i"; } else { cout << "Sum = " << real
<< " + " << imag << "i"; } } };
int main() {
Complex num1, num2, result;
cout << "Enter the first complex number:n";
num1.input(); cout << "Enter the second complex
number:n"; num2.input();

13. Explain the Constructor in C++
In C++, a constructor is a special member function with the same name as the class. It is
automatically invoked when an object of the class is created. Constructors initialize the object's data
members and ensure the object is in a valid state upon creation.
12. What is Polymorphism in C++?
Polymorphism in C++ allows objects of different classes to be treated as objects of a common
superclass. It enables functions to operate on objects of multiple derived classes through
pointers or references to the base class, simplifying code and enhancing ﬂexibility in object-
oriented programming.
The two types of polymorphism in C++ are:
Compile Time Polymorphism
Runtime Polymorphism
Example
#include
using namespace std;
class MyClass {
private:
int num;
public:
// Default constructor
MyClass() {
num = 0;
cout << "Default Constructor Called! Num is set to 0." << endl;
}
// Parameterized constructor
MyClass(int value) {
num = value;
cout << "Parameterized Constructor Called! Num is set to " << num << "." << endl;
}
// Member function to display the value
void display() {
cout << "Value of num: " << num << endl;
}

Output
Explanation
Run Code >>
Watch the Video - Constructor in Cpp
In this example, the MyClass class has a default constructor and a parameterized constructor. When
objects obj1 and obj2 are created, the constructors are automatically called. The default constructor
initializes num to 0, and the parameterized constructor initializes num with the provided value (42 in
this case). The display() member function is used to display the values of num for the created objects.
return 0;
}
// Calling member function to display the values
cout << "Object 1: ";
obj1.display(); // Displays num = 0
cout << "Object 2: ";
obj2.display(); // Displays num = 42
Default Constructor Called! Num is set to 0.
Parameterized Constructor Called! Num is set to 42.
Object 1: Value of num: 0
Object 2: Value of num: 42
};
int main() {
// Creating objects of MyClass using constructors
MyClass obj1; // Calls default constructor
MyClass obj2(42); // Calls parameterized constructor

16. What is a Reference in C++?
In C++, a reference is an alias for a variable. It allows you to use an existing variable through a
different name. References are often used as function parameters to modify variables outside
the function or to avoid unnecessary copying of large data structures, enhancing performance
and readability.
15. What are the C++ Access Specifiers?
C++ access specifiers control the visibility and accessibility of class members. There are three types:
14. Compare Compile-Time Polymorphism and Runtime
Polymorphism in C++
Compile-time Polymorphism
Occurs during compilation.
Method binding is done at compile-time
Any changes we make to the value of ref will show up in x. A reference variable cannot refer to
another variable once it has been initialized. An array of references cannot be declared,
although an
Runtime Polymorphism
Occurs during program execution.
Method binding is done at runtime using virtual
functions and inheritance.
Achieved through inheritance and virtual functions.
Achieved through function overloading
and operator overloading.
Resolves calls at compile-time, resulting
in faster execution.
Examples include function overloading
and templates.
Resolves calls at runtime, allowing flexibility but
incurring slight performance overhead.
Example: Function overriding using virtual functions in
base and derived classes.
Public: Members are accessible from outside the class.
Private: Members are only accessible within the class.
Protected: Members are accessible within the class and its subclasses (derived classes).
Example
int x=10;
int &ref=x; //reference variable
HTML to PDF
array of pointers may.

Function Overloading
It involves defining multiple functions with
the same name but different parameters.
Operator Overloading
Involves defining custom behaviors for C++
operators like +, -, *, etc.
Enables a function to perform different tasks
based on the input arguments.
Allows objects of user-defined classes to work
with operators, extending their functionality.
Overloading a destructor is not feasible. There is just one method to delete an object since
destroyers don't accept parameters. Destructor overloading is therefore not feasible.
Function overloading and operator overloading are both techniques in C++ to provide multiple
definitions for functions or operators, but they differ in their application:
In C++, abstraction refers to the concept of hiding complex implementation details and showing only
the necessary features of an object. It allows programmers to create user-defined data types and
focus on what an object does, rather than how it achieves its functionality, enhancing code simplicity
and reusability.
17. What do you mean by Abstraction in C++?
18. Is Deconstructor Overloading Possible? If Yes then Explain and if
no then why?
19. What is the Difference between Function Overloading and Operator
Overloading?

It
flexibility.
helps improve code readability and Provides a natural syntax for user-defined types,
enhancing code expressiveness and clarity
Destructors in C++ are special member functions of a class that are used to clean up resources
allocated by objects. They have the same name as the class prefixed with a tilde (~) and are
automatically invoked when an object goes out of scope or is explicitly deleted, ensuring proper
resource deallocation.
When a class variable is marked static, memory is set aside for it for the duration of the program.
There is only one copy of the static member, regardless of how many objects of that class have
been produced. This means that all of the objects in that class can access the same static member.
Even in the absence of any class objects, a static member function can still be invoked since it can be
reached with just the class name and the scope resolution operator::
2. Explain Inheritance in C++
20. What are Destructors in C++?
1. What are the Static Members and Static Member Functions in C++?
Syntax
C++ Programming Interview Questions for
Intermediates
X();
public:
class X {
// Constructor for class X
// Destructor for class X ~X();};

Size:
Insertion
Deletion:
Memory
Allocation:
Access Time:
Functionality:
Watch the Video - Inheritance in C++ | Different Types with Examples in C++
Array Contiguous memory
allocation for
elements, allowing direct access
via indexing.
List
Elements are stored in nodes scattered
across memory, accessed
through
pointers, offering dynamic size and
flexibility.
Dynamic size; can grow or shrink during
runtime.
Fixed size; must specify the size
during declaration.
and Array Insertion and deletion can be
inefficient due to shifting elements.
Efficient insertion and deletion
as
elements can be easily added or removed
without moving other nodes.
Linear time access, iterating through
nodes for specific elements.
Constant time access for elements
using indices.
Limited
provide
operations like insertion or deletion.
functionality; doesn't
for
Provides built-in methods for various
built-in methods operations, making it versatile for
dynamic data structures.
The equal to operator == determines if two values are equal. It returns false otherwise; if they are
equal, then it is true.
The assignment operator = gives the left operand the value of the right-side expression.
In C++, inheritance is a fundamental object-oriented programming concept that allows a class
(derived or child class) to inherit properties and behaviors from another class (base or parent class).
Derived classes can access public and protected members of the base class, promoting code
reusability and establishing a relationship between classes. This mechanism enables the creation of
a hierarchy of classes where child classes inherit attributes and methods from their parent,
facilitating efficient and organized code development.
4. What is the difference between an Array and a List in C++?
5. What is Loops in C++? Explain different types of loops in C++
3. Difference between equal to (==) and assignment operator(=)?

Structure:
Use Cases:
Code
Readability:
Initialization:
While Loop Condition is evaluated before
entering the
loop; the loop body may never execute if
the condition is initially false. It's a pre-
test loop, as it checks the
condition before executing the loop's
body.
Do-While Loop
The loop body is executed at least once before
checking the condition; it always runs at least once.
It's a post-test loop, as it ensures the loop body is
executed before condition checking.
For Loop While Loop
For loop initializes a counter variableWhile loop initializes the counter variable
within the loop header. before the loop.
For loop has a built-in structure forWhile loop relies on manual control of
initialization, condition, and increment. these aspects within the loop.
For loops are suitable for iterating aWhile loops are more flexible for looping
specific number of times. until a condition is met or for indefinite
loops.
For loops can be more concise andWhile loops offer greater control but may
easier to read for certain repetitive
tasks.
require more code for simple iterations
While both while and do-while loops in C++ are used for repetitive execution, they differ in their loop
control flow:
In C++, loops are control structures that allow the execution of a block of code repeatedly as long as
a specified condition is true. There are three types of loops in C++:
For Loop: Executes a block of code a specified number of times, with an initialization, condition
check, and increment/decrement statement.
While Loop: Executes a block of code as long as a specified condition is true.
Do-While Loop: Similar to the while loop, but ensures the code block is executed at least once
before checking the condition.
7. What is the difference between a while loop and a do-while loop in
C++?
6. What is the difference between a for loop and a while loop in C++?

Syntax:
Type Safety:
Initialization:
Prefix (++i, --i) Increments or decrements
the variable's
value before its current value is used in the
expression. Changes the original variable
and then
evaluates the expression.
Offers slightly better performance as it
avoids creating a temporary variable.
Postfix (i++, i--)
Uses the current value of the variable in the
expression before incrementing or decrementing it.
Evaluate the expression and then change the
variable.
Involves the creation of a temporary variable to store
the original value, which may have a minor impact on
performance.
In C++, prefix and postfix are used to increment or decrement variables. The key differences between
them are:
new new is an operator in C++ that
automatically
calculates the size of the object being
allocated and returns a pointer to the
appropriate type. The syntax is: new Type; or
new Type[size]; new is type-safe. It allocates
memory for the
specified data type and returns a pointer of
that type. For example, if you allocate
memory for an integer using new, the pointer
returned will be of type int*.
malloc() malloc() is a function in C
that
allocates a specific number of bytes
of memory and returns a pointer to
the first byte. The syntax is:
malloc(size); malloc() does not
provide type
information. It always returns a
pointer to void (void*). You need to
cast the pointer to the appropriate
type before using it.
When you use new, the allocated memory isMemory allocated by malloc() is not
initialized by calling the constructor of the initialized. You need to explicitly set
Suitable for scenarios where the loop may
not need to run at all, based on the
condition.
Useful when you want to guarantee that the loop body
runs at least once, regardless of the initial condition,
such as when taking user input validation.
9. What is the difference between new and malloc() in C++?
8. Discuss the difference between prefix and postfix in C++?

Declared in the base class with the virtual keyword and set to 0.
Has no implementation in the base class.
Forces derived classes to provide an implementation.
Classes containing pure virtual functions are abstract and cannot be instantiated.
Declared in the base class with the virtual keyword.
Can be overridden in derived classes.
Provides a default implementation in the base class.
Objects of the derived class can be used through pointers or references of the base class type.
object (if available). For primitive types like
int, the memory is initialized to zero.
new throws a std::bad_alloc exception if it
fails to allocate memory.
the initial values for the allocated
memory.
malloc() returns a null pointer
(nullptr in C++) if it fails to allocate
memory. Memory allocated with
malloc()
should be deallocated using free().
Return
Value:
Deallocation: Memory allocated with new should be
deallocated using delete for single objects or
delete[] for arrays to avoid memory leaks.
Virtual functions and pure virtual functions are concepts in C++ related to polymorphism and
inheritance:
Function overriding in C++ occurs when a derived class provides a speciﬁc implementation for a
function that is already deﬁned in its base class. To achieve this, the function in the derived class
must have the same name, return type, and parameters as the one in the base class. When an
object of the derived class calls the overridden function, the derived class's implementation is
executed instead of the base class's version, allowing for customization and polymorphic behavior
in object-
oriented programming.
11. What is Function Overriding in C++?
12. What are the various OOPs concepts in C++?
10. What is the difference between virtual functions and pure virtual
functions in C++?
Virtual Functions:
Pure Virtual Functions:

The variables used to hold the address position of another variable are called pointers. The following
operations on a pointer are allowed:
Virtual inheritance in C++ is a mechanism that prevents multiple instances of a base class in a class
hierarchy. It ensures that only one instance of the base class exists when multiple derived classes
inherit from it. This prevents issues like the "diamond problem" where ambiguity arises due to
multiple inheritance paths.
A virtual destructor in C++ is a destructor declared in the base class with the virtual keyword. When a
derived class object is deleted through a pointer to the base class, a virtual destructor ensures that
the derived class's destructor is called, preventing memory leaks and ensuring proper cleanup of
resources in polymorphic hierarchies.
Multiple inheritance in C++ should be used cautiously and in specific scenarios where it simplifies the
design without introducing complexity. It is appropriate when a class needs to inherit properties and
behaviors from more than one unrelated class. For example, in GUI frameworks a class may inherit
from both a graphical component class and an event handling class. However, it requires careful
planning to avoid ambiguity issues, and alternative design patterns like composition or interfaces
should be considered to enhance code readability and maintainability.
In C++, Object-Oriented Programming (OOP) concepts include:
Classes & Objects: Blueprint for creating objects.
Encapsulation: Binding data and methods that operate on the data, restricting direct access.
Inheritance: Creating new classes from existing ones, inheriting properties and behaviors.
Polymorphism: Objects of different classes can be treated as objects of a common base class.
Abstraction: Hiding complex implementation details and showing only essential features.
Constructor & Destructor: Special member functions for object initialization and cleanup,
respectively.
Operator Overloading: Redefining operators for user-defined types.
14. What is virtual inheritance in C++?
15. What is a virtual destructor in C++?
1. Which operations are permitted on pointers?
13. When should we use multiple inheritance in C++?
C++ Programming Interview Questions for Experienced

Increment/Decrement of a Pointer
Addition and Subtraction of integer to a pointer
Comparison of pointers of the same type
delete is used for single objects allocated with new.
delete[] is used for arrays of objects allocated with new[].
delete calls the destructor of the single object before deallocating memory.
delete[] calls the destructors of all objects in the array before deallocating the memory block.
Friend class- In C++, a friend class is a class that is granted access to the private and protected
members of another class. It is declared using the friend keyword in the class declaration. Friend
classes can access private and protected members of the class they are friends with, providing
controlled access for speciﬁc classes.
In C++, the delete operator is used to deallocate memory that was previously allocated using the new
operator. It helps free up memory occupied by dynamically allocated objects, preventing memory
leaks, and managing resources eﬃciently during runtime.
In C++, delete and delete[] are used to deallocate memory previously allocated with new and new[]
operators, respectively. The key differences are:
3. How delete [] is different from delete in C++?
2. What is the purpose of the “delete” operator in C++?
4. What do you know about friend class and friend function in C++?
Example
Example
Deallocation Process:
Memory Allocation Type:
int DNT = new int[100];
// uses DNT for deletion
delete [] DNT;

Run Code >>
Run Code >>
Friend function- In C++ Online Compiler, a friend function is a function that is not a member of a
class but has access to its private and protected members. It is declared inside the class and can
access the class's private and protected data, providing a way to allow external functions special
privileges with a speciﬁc class.
Example
5. What is an Overﬂow Error?
class Class_1st {
// ClassB is a friend class of ClassA
friend class Class_2nd;
statements;
}
class Class_2nd {
statements;
}
class DNT {
statements;
friend dataype function_Name(arguments);
statements;
}
OR
class DNT{
statements'
friend int divide(10,5);
statements;
}

In C++, the Scope Resolution operator (::) is used to specify the class or namespace to which a
particular identifier (such as a variable or function) belongs. It allows access to class members
when there is a naming conflict between local and class-level variables or functions.
The Scope Resolution Operator (::) in C++ is used:
To define member functions outside the class.
To access static members of a class.
To differentiate between class member functions/variables and global functions/variables with
the same name.
To access nested classes or namespaces.
In the context of the C++ Standard Template Library (STL) for nested classes or functions.
In C++, access modifiers control the visibility and accessibility of class members. There are three
access modifiers:
Public:
Members declared as public are accessible from any part of the program.
Public members can be accessed through class objects and pointers.
Private:
Members declared as private are only accessible within the class they are declared in.
Private members cannot be accessed directly from outside the class.
Protected:
Protected members are accessible within the class and its subclasses (derived classes).
They are not accessible from outside the class hierarchy.
Overflow occurs when the value is more than what the data type can handle, an error is produced.
Said another way, it's an error type that falls inside the prescribed range but is valid outside of it.
A variable of size 2,247,483,648 will result in an overflow error, for instance, because the range of the
int data type is –2,147,483,648 to 2,147,483,647.
7. What are the C++ access modifiers?
6. What does the Scope Resolution operator do in C++?
8. Can you compile a program without the main function?

Run Code >>
Indeed, a program may be compiled without a main() call. For instance, Use Macros that define the
main
In C++, an inline function is a function that is expanded in place where it is called, instead of being
executed through a regular function call mechanism. It is declared with the inline keyword and
helps reduce the function call overhead by inserting the function's code directly at the call site.
STL, or Standard Template Library, is a powerful set of C++ template classes and functions that
provides general-purpose data structures and algorithms. It simplifies complex tasks, promotes
code reuse, and enhances efficiency. STL includes containers, algorithms, iterators, and function
objects, making C++ programming more efficient and convenient.
Syntax
Example
9. What is STL?
10. Define inline function. Can we have a recursive inline function in
C++?
// C++ program to demonstrate the
// a program without main()
#include
#define fun main
int fun(void)
{
printf("ScholarHat");
return 0;
}

inline data_type function_name()
{
Body;
}
In C++, an abstract class is a class that cannot be instantiated and is meant to be subclassed by
other classes. It serves as a blueprint for derived classes, defining abstract (pure virtual) methods
without providing their implementations. Here's when and why you use abstract classes:
Incomplete Implementation: Abstract classes contain one or more pure virtual functions without
implementation details.
Derived Class Requirement: Abstract classes are designed to be subclassed. Derived classes
must provide concrete implementations for all pure virtual functions.
Interface Definition: Abstract classes define interfaces, ensuring consistent method signatures
across derived classes.
Polymorphism: Abstract classes enable polymorphism, allowing objects of derived classes to be
treated as objects of the abstract class type.
Forcing Implementation: Abstract classes enforce derived classes to provide specific
functionality, ensuring proper class hierarchy design.
The answer is No; It cannot be recursive.
An inline function cannot be recursive because it simply loads the code into the location from where
it is called, without keeping track of any information on the stack that would be required for recursion.
Additionally, the compiler will automatically disregard an inline keyword placed in front of a recursive
function as it only interprets inlines as suggestions.
A class's static data member is a regular data member that is preceded by the term static. When a
program runs, it runs before main() and is initialized to 0 upon the creation of the class's first object.
Use abstract classes when you want to create a common interface for a group of related classes,
ensuring that derived classes provide specific implementations for essential methods while
allowing for polymorphic behavior.
11. What is an abstract class and when do you use it?
12. What are the static data members and static member functions in
C++?

Its scope is lifetime, but it is only accessible to a particular class.
The properties (lifetime and visibility) of a variable or function are defined by the storage class. These
properties often aid in tracking a variable's existence while a program runs.
In C++, a namespace is a declarative region that provides a scope for identifiers to avoid naming
conflicts. Here's a concise explanation within 80 words, using points:
Scope Isolation: Namespaces prevent naming collisions by encapsulating identifiers within a
distinct scope.
Syntax: Declared using the namespace keyword followed by the namespace name and a code
block {}.
Usage: Members like variables, functions, and classes can be declared inside namespaces.
Access Control: Namespaced elements are accessed using the scope resolution operator ::
Example: namespace MyNamespace { int x; void func(); }
Avoiding Ambiguity: Helps organize code, making it easier to read, maintain, and avoid conflicts
in larger projects.
The member function that is used to access other static members of the data or other static member
functions is known as the static member function. A static keyword is also used to specify it. Either
the class name or class objects can be used to access the static member method.
Syntax
Syntax
Syntax
static Data_Type Data_Member;
classname::function name(parameter)
storage_class var_data_type var_name;
13. Define namespace in C++.
14. Define storage class in C++ and name some of them

In C++, there are four primary storage classes, each serving different purposes in controlling the
scope, lifetime, and visibility of variables and functions:
Auto:
Local variables declared within a block are of automatic storage class by default.
They are created when the block is entered and destroyed when the block is exited.
Static:
Variables declared with the static keyword have a lifetime throughout the program.
Static local variables retain their values between function calls.
Static global variables are accessible only within the file where they are declared.
Extern:
Variables declared with the extern keyword are defined elsewhere in the program.
They have global scope and can be accessed across multiple files.
Register:
Variables declared with the register keyword suggest the compiler store them in a register for
faster access.
Note: The register keyword is deprecated in modern C++ and has limited usage.
In conclusion, mastering these top 50 C++ language interview questions is pivotal for aspiring
programmers. These insights into fundamental concepts, data structures, and algorithms equip
candidates with the knowledge needed to succeed in technical interviews. You can also consider
doing our C++ tutorial from Scholar Hat by Dot Net Tricks to upskill your career. Practice,
understanding, and confidence in these areas will undoubtedly pave the way to a successful C++
programming career.
As implied by its name, the mutable storage class specifier modifies a class data member only when
it is applied to an object that is defined as const, even if the member is a part of the object. Reference,
static, or const members can't employ the mutable specifier. This pointer provided to the function
becomes const when the function is declared as const.
15. What is a mutable storage class specifier? How can they be used?
Conclusion

FAQs
Q1. How should I prepare for a C++ programming interview?
Q4. What are the different levels of diﬃculty in C++ interview
questions?
Q2. What types of questions can I expect in a C++ interview?
Q5. What are some common mistakes candidates make in C++
interviews?
Q3. What are the main topics typically covered in C++ interviews?
C++ interview questions can range from basic syntax and data types to complex memory
management and design patterns. They are typically categorized as:
In a C++ interview, you can expect a mix of theoretical questions to evaluate your understanding of
language features and practical coding problems to assess your problem-solving skills. Questions
may cover topics such as memory management, data structures, algorithm design, and the effective
use of C++ features like templates and STL containers.
To prepare for a C++ programming interview, it's important to have a strong grasp of fundamental
concepts such as classes, objects, inheritance, and polymorphism. Additionally, practice solving
coding problems, review commonly used C++ libraries and frameworks, and understand advanced
topics like smart pointers, move semantics, and multithreading.
Beginner: Understanding core concepts like variables, operators, control ﬂow, functions, and
basic pointers.
Intermediate: Arrays, structures, unions, dynamic memory allocation (new/delete), references,
inheritance, and polymorphism.
Advanced: Templates, STL (Standard Template Library), multithreading, smart pointers,
exception handling, and design patterns.
C++ interviews often focus on core concepts such as object-oriented programming (OOP) principles
(inheritance, polymorphism, encapsulation), memory management (stack vs. heap), templates,
exception handling, standard template library (STL), pointers, references, and operator overloading.

Confusing pointers and references: Grasping the subtle differences is crucial.
Struggling with memory management: Understanding memory leaks and proper deallocation is
key.
Overlooking the importance of clean code: Write readable, well-commented, and eﬃcient code.
Neglecting object-oriented concepts: OOP principles are fundamental in modern C++.
Lacking familiarity with the STL: Utilize the power of ready-made data structures and algorithms.

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