Top C++ Programming Interview Questions and Answers (Section-Wise)<\/strong><\/h2>\n\n\n\nI have divided all these important C++ Programming interview questions and answers into various sections for your ease of learning. I recommend covering the beginner-level questions as a must and then going through all the sections one by one so that you can gain a well-rounded knowledge of how these interviews are undertaken and how much and what you should prepare.<\/p>\n\n\n\n![\"c++](\"https:\/\/www.guvi.in\/blog\/wp-content\/uploads\/2025\/01\/Top-C-Programming-Interview\u2028Questions-and-Answers-Section-Wise-1200x630.png\" "\\"\\"")
<\/figure>\n\n\n\nBeginner Level C++ Programming Interview Questions and Answers<\/strong><\/h3>\n\n\n\n1. What is C++, and how is it different from C?<\/strong><\/p>\n\n\n\nAnswer:<\/strong><\/p>\n\n\n\nC++<\/a> is an object-oriented programming language that extends C. Differences include:<\/p>\n\n\n\n\n- Object-Oriented Features<\/strong>: Supports classes, objects, inheritance, and polymorphism.<\/li>\n\n\n\n
- Function Overloading and Templates<\/strong>: Enables code reuse.<\/li>\n\n\n\n
- STL (Standard Template Library)<\/strong>: Provides data structures and algorithms.<\/li>\n\n\n\n
- Namespace Support<\/strong>: Prevents name conflicts.<\/li>\n\n\n\n
- Inline Functions<\/strong>: Reduce function call overhead.<\/li>\n<\/ul>\n\n\n\n
2. What are the key features of C++?<\/strong><\/p>\n\n\n\nAnswer:<\/strong><\/p>\n\n\n\n\n- Object-Oriented Programming<\/strong><\/a>: Supports encapsulation, inheritance, and polymorphism.<\/li>\n\n\n\n
- Templates<\/strong>: Generic programming via function and class templates.<\/li>\n\n\n\n
- STL<\/strong>: Provides reusable libraries for containers, algorithms, and iterators.<\/li>\n\n\n\n
- Platform Independence<\/strong>: Compiled code is OS-independent.<\/li>\n\n\n\n
- Low-Level Manipulation<\/strong>: Supports pointer arithmetic and memory management.<\/li>\n<\/ul>\n\n\n\n
3. What is the difference between a class and an object?<\/strong><\/p>\n\n\n\nAnswer:<\/strong><\/p>\n\n\n\n\n- Class<\/strong>: A blueprint or template that defines attributes and behaviors.<\/li>\n<\/ul>\n\n\n\n
Object<\/strong>: An instance of a class.<\/p>\n\n\n\nclass Car { \/\/ Class definition\npublic:\n string model;\n void drive() { cout << \"Driving \" << model; }\n};\nCar c; \/\/ Object instantiation<\/code><\/pre>\n\n\n\n4. Explain the concept of a constructor in C++.<\/strong><\/p>\n\n\n\nAnswer:
<\/strong>A constructor<\/a><\/strong> is a special member function with the same name as the class. It initializes objects.<\/p>\n\n\n\n\n- Default Constructor<\/strong>: Takes no arguments.<\/li>\n\n\n\n
- Parameterized Constructor<\/strong>: Accepts arguments.<\/li>\n<\/ul>\n\n\n\n
Copy Constructor<\/strong>: Initializes an object from another object of the same class.<\/p>\n\n\n\nclass MyClass {\npublic:\n MyClass() { cout << \"Default constructor\"; }\n MyClass(int x) { cout << \"Parameterized constructor: \" << x; }\n MyClass(const MyClass &obj) { cout << \"Copy constructor\"; }\n};<\/code><\/pre>\n\n\n\n5. What is a destructor in C++?Answer:
<\/strong>A destructor in C++ is a special member function called when an object is destroyed. It cleans up resources.<\/p>\n\n\n\nclass MyClass {\npublic:\n ~MyClass() { cout << \"Destructor called\"; }\n};<\/code><\/pre>\n\n\n\n6. What is the difference between a <\/strong>struct and a class in C++?<\/strong><\/p>\n\n\n\nAnswer:<\/strong>
<\/strong><\/p>\n\n\n\nAspect<\/strong><\/td>struct<\/strong><\/td>class<\/strong><\/td><\/tr>Default Access<\/strong><\/td>Members are public by default.<\/td> Members are private by default.<\/td><\/tr> Purpose<\/strong><\/td>Primarily used for simple data grouping.<\/td> Used for complex object modeling and encapsulation.<\/td><\/tr> Inheritance<\/strong><\/td>Inherits publicly by default.<\/td> Inherits privately by default.<\/td><\/tr> Encapsulation<\/strong><\/td>Limited due to default public access.<\/td> Fully supports encapsulation.<\/td><\/tr> Use Case<\/strong><\/td>Lightweight, for plain data structures.<\/td> Full-featured objects with methods and access control.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nKey Insight:<\/strong>
<\/strong>Both are almost identical in C++ except for the default access specifier and typical use cases. Classes are preferred for object-oriented programming, while structs are used for simpler tasks.<\/p>\n\n\n\n7. What is function overloading?<\/strong><\/p>\n\n\n\nAnswer:<\/strong><\/p>\n\n\n\nFunction overloading is a feature in C++ that allows multiple functions with the same name to coexist in a program, differentiated by their parameter lists. The compiler distinguishes between these functions based on the number, types, or order of their parameters (also known as the function’s signature).<\/p>\n\n\n\n
Key Points:<\/strong><\/p>\n\n\n\n\n- Enhances code readability and reusability.<\/li>\n\n\n\n
- Does not<\/strong> depend on the return type of the function.<\/li>\n\n\n\n
- Achieved through compile-time polymorphism.<\/li>\n<\/ul>\n\n\n\n
Example:<\/strong><\/p>\n\n\n\n#include <iostream>\nusing namespace std;\n\nvoid display(int x) {\n cout << \"Integer: \" << x << endl;\n}\n\nvoid display(double x) {\n cout << \"Double: \" << x << endl;\n}\n\nint main() {\n display(10); \/\/ Calls display(int)\n display(10.5); \/\/ Calls display(double)\n return 0;\n}<\/code><\/pre>\n\n\n\n8. Explain default arguments in functions.<\/strong><\/p>\n\n\n\nAnswer:<\/strong><\/p>\n\n\n\n\n- Definition: Default arguments allow functions to use predefined values if no corresponding argument is passed by the caller.<\/li>\n\n\n\n
- Key Points:\n
\n- Default arguments are defined in the function declaration.<\/li>\n\n\n\n
- They must be assigned from right to left in the parameter list.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n
Example:<\/p>\n\n\n\n
void greet(string name = \"Guest\") {\n cout << \"Hello, \" << name << endl;\n}\ngreet(); \/\/ Output: Hello, Guest\ngreet(\"Alice\"); \/\/ Output: Hello, Alice<\/code><\/pre>\n\n\n\n9. What are inline functions?<\/strong><\/p>\n\n\n\nAnswer:<\/strong>
<\/strong>Definition: <\/strong>Inline functions are small functions suggested to the compiler to expand directly at the point of call instead of using the typical function call mechanism.<\/p>\n\n\n\nKey Points:<\/strong><\/p>\n\n\n\n\n- Declared using the inline keyword.<\/li>\n\n\n\n
- Helps reduce function call overhead for small, frequently used functions.<\/li>\n\n\n\n
- The compiler may ignore the inline request based on function complexity.<\/li>\n<\/ul>\n\n\n\n
Example:<\/strong><\/p>\n\n\n\ninline int square(int x) {\n return x * x;\n}\ncout << square(4); \/\/ Output: 16<\/code><\/pre>\n\n\n\n10. Explain the concept of namespaces in C++.<\/strong><\/p>\n\n\n\nAnswer:<\/strong>
Definition: Namespaces provide a way to group related identifiers (like classes, variables, and functions) to avoid naming conflicts in large projects.<\/p>\n\n\n\nKey Points:<\/strong><\/p>\n\n\n\n\n- Declared using the namespace keyword.<\/li>\n\n\n\n
- Accessed using the scope resolution operator (::).<\/li>\n<\/ul>\n\n\n\n
Example:<\/strong><\/p>\n\n\n\nnamespace Math {\n int add(int a, int b) { return a + b; }\n}\ncout << Math::add(3, 5); \/\/ Output: 8<\/code><\/pre>\n\n\n\nThe std namespace, which contains the Standard Library, is a common example.<\/p>\n\n\n\n
11. Write a program to swap two numbers using a temporary variable.<\/strong><\/p>\n\n\n\nAnswer:<\/strong><\/p>\n\n\n\n#include <iostream>\nusing namespace std;\n\nint main() {\n int a = 5, b = 10;\n cout << \"Before Swap: a = \" << a << \", b = \" << b << endl;\n\n int temp = a; \/\/ Store value of a in temp\n a = b; \/\/ Assign value of b to a\n b = temp; \/\/ Assign value of temp to b\n\n cout << \"After Swap: a = \" << a << \", b = \" << b << endl;\n return 0;\n}<\/code><\/pre>\n\n\n\nOutput:<\/strong><\/p>\n\n\n\nless<\/p>\n\n\n\n
Copy code<\/p>\n\n\n\n
Before Swap: a = 5, b = 10 <\/p>\n\n\n\n
After Swap: a = 10, b = 5 <\/p>\n\n\n\n
Explanation:<\/strong><\/p>\n\n\n\n\n- Store the value of a in temp.<\/li>\n\n\n\n
- Assign the value of b to a.<\/li>\n\n\n\n
- Assign the value of temp (original value of a) to b.<\/li>\n<\/ol>\n\n\n\n
12. What is the purpose of the sizeof operator in C++?<\/strong><\/p>\n\n\n\nAnswer:<\/strong><\/p>\n\n\n\nThe sizeof operator in C++ is used to determine the size, in bytes, of a data type, variable, or object at compile time. It helps in understanding memory allocation and is often used for low-level programming tasks like memory management or working with hardware.<\/p>\n\n\n\n
Example:<\/p>\n\n\n\n
#include <iostream>\nusing namespace std;\n\nint main() {\n cout << \"Size of int: \" << sizeof(int) << \" bytes\\n\"; \/\/ Typically 4 bytes\n cout << \"Size of double: \" << sizeof(double) << \" bytes\\n\"; \/\/ Typically 8 bytes\n return 0;\n}<\/code><\/pre>\n\n\n\nKey Features:<\/p>\n\n\n\n
\n- Evaluated at compile time.<\/li>\n\n\n\n
- Includes padding bytes for structure alignment.<\/li>\n\n\n\n
- Commonly used for array size calculation and type alignment.<\/li>\n<\/ul>\n\n\n\n
Intermediate Level C++ Programming Interview Questions and Answers<\/strong><\/h3>\n\n\n\n13. What is the difference between <\/strong>new<\/strong> and <\/strong>malloc<\/strong>?<\/strong><\/p>\n\n\n\nAnswer:<\/strong><\/p>\n\n\n\n
<\/figure>\n\n\n\nBeginner Level C++ Programming Interview Questions and Answers<\/strong><\/h3>\n\n\n\n1. What is C++, and how is it different from C?<\/strong><\/p>\n\n\n\nAnswer:<\/strong><\/p>\n\n\n\nC++<\/a> is an object-oriented programming language that extends C. Differences include:<\/p>\n\n\n\n\n- Object-Oriented Features<\/strong>: Supports classes, objects, inheritance, and polymorphism.<\/li>\n\n\n\n
- Function Overloading and Templates<\/strong>: Enables code reuse.<\/li>\n\n\n\n
- STL (Standard Template Library)<\/strong>: Provides data structures and algorithms.<\/li>\n\n\n\n
- Namespace Support<\/strong>: Prevents name conflicts.<\/li>\n\n\n\n
- Inline Functions<\/strong>: Reduce function call overhead.<\/li>\n<\/ul>\n\n\n\n
2. What are the key features of C++?<\/strong><\/p>\n\n\n\nAnswer:<\/strong><\/p>\n\n\n\n\n- Object-Oriented Programming<\/strong><\/a>: Supports encapsulation, inheritance, and polymorphism.<\/li>\n\n\n\n
- Templates<\/strong>: Generic programming via function and class templates.<\/li>\n\n\n\n
- STL<\/strong>: Provides reusable libraries for containers, algorithms, and iterators.<\/li>\n\n\n\n
- Platform Independence<\/strong>: Compiled code is OS-independent.<\/li>\n\n\n\n
- Low-Level Manipulation<\/strong>: Supports pointer arithmetic and memory management.<\/li>\n<\/ul>\n\n\n\n
3. What is the difference between a class and an object?<\/strong><\/p>\n\n\n\nAnswer:<\/strong><\/p>\n\n\n\n\n- Class<\/strong>: A blueprint or template that defines attributes and behaviors.<\/li>\n<\/ul>\n\n\n\n
Object<\/strong>: An instance of a class.<\/p>\n\n\n\nclass Car { \/\/ Class definition\npublic:\n string model;\n void drive() { cout << \"Driving \" << model; }\n};\nCar c; \/\/ Object instantiation<\/code><\/pre>\n\n\n\n4. Explain the concept of a constructor in C++.<\/strong><\/p>\n\n\n\nAnswer:
<\/strong>A constructor<\/a><\/strong> is a special member function with the same name as the class. It initializes objects.<\/p>\n\n\n\n\n- Default Constructor<\/strong>: Takes no arguments.<\/li>\n\n\n\n
- Parameterized Constructor<\/strong>: Accepts arguments.<\/li>\n<\/ul>\n\n\n\n
Copy Constructor<\/strong>: Initializes an object from another object of the same class.<\/p>\n\n\n\nclass MyClass {\npublic:\n MyClass() { cout << \"Default constructor\"; }\n MyClass(int x) { cout << \"Parameterized constructor: \" << x; }\n MyClass(const MyClass &obj) { cout << \"Copy constructor\"; }\n};<\/code><\/pre>\n\n\n\n5. What is a destructor in C++?Answer:
<\/strong>A destructor in C++ is a special member function called when an object is destroyed. It cleans up resources.<\/p>\n\n\n\nclass MyClass {\npublic:\n ~MyClass() { cout << \"Destructor called\"; }\n};<\/code><\/pre>\n\n\n\n6. What is the difference between a <\/strong>struct and a class in C++?<\/strong><\/p>\n\n\n\nAnswer:<\/strong>
<\/strong><\/p>\n\n\n\nAspect<\/strong><\/td>struct<\/strong><\/td>class<\/strong><\/td><\/tr>Default Access<\/strong><\/td>Members are public by default.<\/td> Members are private by default.<\/td><\/tr> Purpose<\/strong><\/td>Primarily used for simple data grouping.<\/td> Used for complex object modeling and encapsulation.<\/td><\/tr> Inheritance<\/strong><\/td>Inherits publicly by default.<\/td> Inherits privately by default.<\/td><\/tr> Encapsulation<\/strong><\/td>Limited due to default public access.<\/td> Fully supports encapsulation.<\/td><\/tr> Use Case<\/strong><\/td>Lightweight, for plain data structures.<\/td> Full-featured objects with methods and access control.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\nKey Insight:<\/strong>
<\/strong>Both are almost identical in C++ except for the default access specifier and typical use cases. Classes are preferred for object-oriented programming, while structs are used for simpler tasks.<\/p>\n\n\n\n7. What is function overloading?<\/strong><\/p>\n\n\n\nAnswer:<\/strong><\/p>\n\n\n\nFunction overloading is a feature in C++ that allows multiple functions with the same name to coexist in a program, differentiated by their parameter lists. The compiler distinguishes between these functions based on the number, types, or order of their parameters (also known as the function’s signature).<\/p>\n\n\n\n
Key Points:<\/strong><\/p>\n\n\n\n\n- Enhances code readability and reusability.<\/li>\n\n\n\n
- Does not<\/strong> depend on the return type of the function.<\/li>\n\n\n\n
- Achieved through compile-time polymorphism.<\/li>\n<\/ul>\n\n\n\n
Example:<\/strong><\/p>\n\n\n\n#include <iostream>\nusing namespace std;\n\nvoid display(int x) {\n cout << \"Integer: \" << x << endl;\n}\n\nvoid display(double x) {\n cout << \"Double: \" << x << endl;\n}\n\nint main() {\n display(10); \/\/ Calls display(int)\n display(10.5); \/\/ Calls display(double)\n return 0;\n}<\/code><\/pre>\n\n\n\n8. Explain default arguments in functions.<\/strong><\/p>\n\n\n\nAnswer:<\/strong><\/p>\n\n\n\n\n- Definition: Default arguments allow functions to use predefined values if no corresponding argument is passed by the caller.<\/li>\n\n\n\n
- Key Points:\n
\n- Default arguments are defined in the function declaration.<\/li>\n\n\n\n
- They must be assigned from right to left in the parameter list.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n
Example:<\/p>\n\n\n\n
void greet(string name = \"Guest\") {\n cout << \"Hello, \" << name << endl;\n}\ngreet(); \/\/ Output: Hello, Guest\ngreet(\"Alice\"); \/\/ Output: Hello, Alice<\/code><\/pre>\n\n\n\n9. What are inline functions?<\/strong><\/p>\n\n\n\nAnswer:<\/strong>
<\/strong>Definition: <\/strong>Inline functions are small functions suggested to the compiler to expand directly at the point of call instead of using the typical function call mechanism.<\/p>\n\n\n\nKey Points:<\/strong><\/p>\n\n\n\n\n- Declared using the inline keyword.<\/li>\n\n\n\n
- Helps reduce function call overhead for small, frequently used functions.<\/li>\n\n\n\n
- The compiler may ignore the inline request based on function complexity.<\/li>\n<\/ul>\n\n\n\n
Example:<\/strong><\/p>\n\n\n\ninline int square(int x) {\n return x * x;\n}\ncout << square(4); \/\/ Output: 16<\/code><\/pre>\n\n\n\n10. Explain the concept of namespaces in C++.<\/strong><\/p>\n\n\n\nAnswer:<\/strong>
Definition: Namespaces provide a way to group related identifiers (like classes, variables, and functions) to avoid naming conflicts in large projects.<\/p>\n\n\n\nKey Points:<\/strong><\/p>\n\n\n\n\n- Declared using the namespace keyword.<\/li>\n\n\n\n
- Accessed using the scope resolution operator (::).<\/li>\n<\/ul>\n\n\n\n
Example:<\/strong><\/p>\n\n\n\nnamespace Math {\n int add(int a, int b) { return a + b; }\n}\ncout << Math::add(3, 5); \/\/ Output: 8<\/code><\/pre>\n\n\n\nThe std namespace, which contains the Standard Library, is a common example.<\/p>\n\n\n\n
11. Write a program to swap two numbers using a temporary variable.<\/strong><\/p>\n\n\n\nAnswer:<\/strong><\/p>\n\n\n\n#include <iostream>\nusing namespace std;\n\nint main() {\n int a = 5, b = 10;\n cout << \"Before Swap: a = \" << a << \", b = \" << b << endl;\n\n int temp = a; \/\/ Store value of a in temp\n a = b; \/\/ Assign value of b to a\n b = temp; \/\/ Assign value of temp to b\n\n cout << \"After Swap: a = \" << a << \", b = \" << b << endl;\n return 0;\n}<\/code><\/pre>\n\n\n\nOutput:<\/strong><\/p>\n\n\n\nless<\/p>\n\n\n\n
Copy code<\/p>\n\n\n\n
Before Swap: a = 5, b = 10 <\/p>\n\n\n\n
After Swap: a = 10, b = 5 <\/p>\n\n\n\n
Explanation:<\/strong><\/p>\n\n\n\n\n- Store the value of a in temp.<\/li>\n\n\n\n
- Assign the value of b to a.<\/li>\n\n\n\n
- Assign the value of temp (original value of a) to b.<\/li>\n<\/ol>\n\n\n\n
12. What is the purpose of the sizeof operator in C++?<\/strong><\/p>\n\n\n\nAnswer:<\/strong><\/p>\n\n\n\nThe sizeof operator in C++ is used to determine the size, in bytes, of a data type, variable, or object at compile time. It helps in understanding memory allocation and is often used for low-level programming tasks like memory management or working with hardware.<\/p>\n\n\n\n
Example:<\/p>\n\n\n\n
#include <iostream>\nusing namespace std;\n\nint main() {\n cout << \"Size of int: \" << sizeof(int) << \" bytes\\n\"; \/\/ Typically 4 bytes\n cout << \"Size of double: \" << sizeof(double) << \" bytes\\n\"; \/\/ Typically 8 bytes\n return 0;\n}<\/code><\/pre>\n\n\n\nKey Features:<\/p>\n\n\n\n
\n- Evaluated at compile time.<\/li>\n\n\n\n
- Includes padding bytes for structure alignment.<\/li>\n\n\n\n
- Commonly used for array size calculation and type alignment.<\/li>\n<\/ul>\n\n\n\n
Intermediate Level C++ Programming Interview Questions and Answers<\/strong><\/h3>\n\n\n\n13. What is the difference between <\/strong>new<\/strong> and <\/strong>malloc<\/strong>?<\/strong><\/p>\n\n\n\nAnswer:<\/strong><\/p>\n\n\n\n
Answer:<\/strong><\/p>\n\n\n\n C++<\/a> is an object-oriented programming language that extends C. Differences include:<\/p>\n\n\n\n 2. What are the key features of C++?<\/strong><\/p>\n\n\n\n Answer:<\/strong><\/p>\n\n\n\n 3. What is the difference between a class and an object?<\/strong><\/p>\n\n\n\n Answer:<\/strong><\/p>\n\n\n\n Object<\/strong>: An instance of a class.<\/p>\n\n\n\n 4. Explain the concept of a constructor in C++.<\/strong><\/p>\n\n\n\n Answer: Copy Constructor<\/strong>: Initializes an object from another object of the same class.<\/p>\n\n\n\n 5. What is a destructor in C++?Answer: 6. What is the difference between a <\/strong>struct and a class in C++?<\/strong><\/p>\n\n\n\n Answer:<\/strong> Key Insight:<\/strong> 7. What is function overloading?<\/strong><\/p>\n\n\n\n Answer:<\/strong><\/p>\n\n\n\n Function overloading is a feature in C++ that allows multiple functions with the same name to coexist in a program, differentiated by their parameter lists. The compiler distinguishes between these functions based on the number, types, or order of their parameters (also known as the function’s signature).<\/p>\n\n\n\n Key Points:<\/strong><\/p>\n\n\n\n Example:<\/strong><\/p>\n\n\n\n 8. Explain default arguments in functions.<\/strong><\/p>\n\n\n\n Answer:<\/strong><\/p>\n\n\n\n Example:<\/p>\n\n\n\n 9. What are inline functions?<\/strong><\/p>\n\n\n\n Answer:<\/strong> Key Points:<\/strong><\/p>\n\n\n\n Example:<\/strong><\/p>\n\n\n\n 10. Explain the concept of namespaces in C++.<\/strong><\/p>\n\n\n\n Answer:<\/strong> Key Points:<\/strong><\/p>\n\n\n\n Example:<\/strong><\/p>\n\n\n\n The std namespace, which contains the Standard Library, is a common example.<\/p>\n\n\n\n 11. Write a program to swap two numbers using a temporary variable.<\/strong><\/p>\n\n\n\n Answer:<\/strong><\/p>\n\n\n\n Output:<\/strong><\/p>\n\n\n\n less<\/p>\n\n\n\n Copy code<\/p>\n\n\n\n Before Swap: a = 5, b = 10 <\/p>\n\n\n\n After Swap: a = 10, b = 5 <\/p>\n\n\n\n Explanation:<\/strong><\/p>\n\n\n\n 12. What is the purpose of the sizeof operator in C++?<\/strong><\/p>\n\n\n\n Answer:<\/strong><\/p>\n\n\n\n The sizeof operator in C++ is used to determine the size, in bytes, of a data type, variable, or object at compile time. It helps in understanding memory allocation and is often used for low-level programming tasks like memory management or working with hardware.<\/p>\n\n\n\n Example:<\/p>\n\n\n\n Key Features:<\/p>\n\n\n\n 13. What is the difference between <\/strong>new<\/strong> and <\/strong>malloc<\/strong>?<\/strong><\/p>\n\n\n\n Answer:<\/strong><\/p>\n\n\n\n\n
\n
\n
class Car { \/\/ Class definition\npublic:\n string model;\n void drive() { cout << \"Driving \" << model; }\n};\nCar c; \/\/ Object instantiation<\/code><\/pre>\n\n\n\n
<\/strong>A constructor<\/a><\/strong> is a special member function with the same name as the class. It initializes objects.<\/p>\n\n\n\n\n
class MyClass {\npublic:\n MyClass() { cout << \"Default constructor\"; }\n MyClass(int x) { cout << \"Parameterized constructor: \" << x; }\n MyClass(const MyClass &obj) { cout << \"Copy constructor\"; }\n};<\/code><\/pre>\n\n\n\n
<\/strong>A destructor in C++ is a special member function called when an object is destroyed. It cleans up resources.<\/p>\n\n\n\nclass MyClass {\npublic:\n ~MyClass() { cout << \"Destructor called\"; }\n};<\/code><\/pre>\n\n\n\n
<\/strong><\/p>\n\n\n\nAspect<\/strong><\/td> struct<\/strong><\/td> class<\/strong><\/td><\/tr> Default Access<\/strong><\/td> Members are public by default.<\/td> Members are private by default.<\/td><\/tr> Purpose<\/strong><\/td> Primarily used for simple data grouping.<\/td> Used for complex object modeling and encapsulation.<\/td><\/tr> Inheritance<\/strong><\/td> Inherits publicly by default.<\/td> Inherits privately by default.<\/td><\/tr> Encapsulation<\/strong><\/td> Limited due to default public access.<\/td> Fully supports encapsulation.<\/td><\/tr> Use Case<\/strong><\/td> Lightweight, for plain data structures.<\/td> Full-featured objects with methods and access control.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n
<\/strong>Both are almost identical in C++ except for the default access specifier and typical use cases. Classes are preferred for object-oriented programming, while structs are used for simpler tasks.<\/p>\n\n\n\n\n
#include <iostream>\nusing namespace std;\n\nvoid display(int x) {\n cout << \"Integer: \" << x << endl;\n}\n\nvoid display(double x) {\n cout << \"Double: \" << x << endl;\n}\n\nint main() {\n display(10); \/\/ Calls display(int)\n display(10.5); \/\/ Calls display(double)\n return 0;\n}<\/code><\/pre>\n\n\n\n\n
\n
void greet(string name = \"Guest\") {\n cout << \"Hello, \" << name << endl;\n}\ngreet(); \/\/ Output: Hello, Guest\ngreet(\"Alice\"); \/\/ Output: Hello, Alice<\/code><\/pre>\n\n\n\n
<\/strong>Definition: <\/strong>Inline functions are small functions suggested to the compiler to expand directly at the point of call instead of using the typical function call mechanism.<\/p>\n\n\n\n\n
inline int square(int x) {\n return x * x;\n}\ncout << square(4); \/\/ Output: 16<\/code><\/pre>\n\n\n\n
Definition: Namespaces provide a way to group related identifiers (like classes, variables, and functions) to avoid naming conflicts in large projects.<\/p>\n\n\n\n\n
namespace Math {\n int add(int a, int b) { return a + b; }\n}\ncout << Math::add(3, 5); \/\/ Output: 8<\/code><\/pre>\n\n\n\n#include <iostream>\nusing namespace std;\n\nint main() {\n int a = 5, b = 10;\n cout << \"Before Swap: a = \" << a << \", b = \" << b << endl;\n\n int temp = a; \/\/ Store value of a in temp\n a = b; \/\/ Assign value of b to a\n b = temp; \/\/ Assign value of temp to b\n\n cout << \"After Swap: a = \" << a << \", b = \" << b << endl;\n return 0;\n}<\/code><\/pre>\n\n\n\n\n
#include <iostream>\nusing namespace std;\n\nint main() {\n cout << \"Size of int: \" << sizeof(int) << \" bytes\\n\"; \/\/ Typically 4 bytes\n cout << \"Size of double: \" << sizeof(double) << \" bytes\\n\"; \/\/ Typically 8 bytes\n return 0;\n}<\/code><\/pre>\n\n\n\n\n
Intermediate Level C++ Programming Interview Questions and Answers<\/strong><\/h3>\n\n\n\n