HCLTech C Developer Interview Questions and Answers

20 - MCQ test related C&C++ basic to advance
2 - coding questions -
1) create class which allows only one instance creation at a time if you try to create another before deleting existing object then class should throw exception..

2) find the distance between leftmost string and rightmost string(string's chars order doesn't matter) In a given long shuffled string.
Ex :-
Shuffled string = "xaxxcxbxxxcxxaxxbx"
target string= "abc"
Ans: 3
(Leftmost string is last index 6
Right most is 9 so 9-6=3)
Note:- other chars not necessarily 'x' it can be any

Q1. Explain oops concepts
Ans. 
OOP is a programming paradigm based on the concept of objects, which can contain data and code to manipulate that data.
• OOP focuses on creating objects that interact with each other to solve complex problems.

• Encapsulation: Objects encapsulate data and behavior within a single unit.

• Inheritance: Objects can inherit attributes and methods from other objects.

• Polymorphism: Objects can take on different forms or have multiple...read more
Answered by AI
Add your answer
Q2. Runtime polymorphism with example
Ans. 
Runtime polymorphism allows objects of different classes to be treated as objects of a common superclass.
• Use virtual functions in base class and override them in derived classes

• Use pointers or references of base class to call derived class methods

• Example: Animal class with virtual function 'makeSound', Dog and Cat classes overriding 'makeSound'
Answered by AI
Add your answer
Q3. Vtable and Vptr working
Ans. 
Vtable and Vptr are mechanisms in C++ for supporting dynamic polymorphism through virtual functions.
• Vtable (Virtual Table) is a static table created by the compiler for each class with virtual functions.

• Vptr (Virtual Pointer) is a pointer in each object instance that points to the Vtable of its class.

• When a virtual function is called, the Vptr is used to look up the correct function in the Vtable.

• Example: If class A ha...read more
Answered by AI
Add your answer
Q4. Abstraction and pure virtual function
Add your answer
Q5. Smart pointers
Add your answer
Q6. Implementation of STL libraries any container class ex:- Vector
Ans. 
STL libraries provide efficient and easy-to-use container classes like Vector for storing and manipulating data.
• STL Vector is a dynamic array that can resize itself automatically.

• It provides random access to elements, similar to arrays.

• Vector supports various operations like push_back, pop_back, insert, erase, etc.

• Example: std::vector<int> numbers = {1, 2, 3, 4, 5};
Answered by AI
Add your answer
Q7. Singleton class creation (code) what is use of it ?
Ans. 
Singleton class ensures only one instance of a class is created and provides a global point of access to it.
• Ensures only one instance of a class is created

• Provides a global point of access to the instance

• Useful for managing global resources or settings
Answered by AI
Add your answer
Q8. SQL simple questions
Add your answer
Q9. What is the use of Mutex
Ans. 
Mutex is used in multithreading to prevent multiple threads from accessing shared resources simultaneously.
• Mutex stands for mutual exclusion and is used to synchronize access to shared resources in multithreaded programs.

• It allows only one thread to access the shared resource at a time, preventing data corruption or race conditions.

• Mutexes are typically used in critical sections of code where data integrity is importan...read more
Answered by AI
Add your answer
Q10. Be strong in theoretically (why, what when to use the concept)
Add your answer

Q1. Bit shift 1 by 4 position from LSB
Ans. 
Bit shift 1 by 4 positions from LSB results in 16
• Use the left shift operator (<<) to shift the bits by 4 positions

• 1 << 4 = 16
Answered by AI
Add your answer
Q2. Copy one string to another without using any standard function
Ans. 
Use a loop to copy characters from one string to another
• Create two character arrays to store the strings

• Use a loop to iterate through each character of the source string and copy it to the destination string

• Add a null terminator at the end of the destination string to mark the end of the copied string
Answered by AI
Add your answer
Q3. What's function pointer and what's it's signature
Ans. 
A function pointer is a variable that stores the address of a function. Its signature includes the return type and parameter types of the function.
• Function pointers allow for dynamic function calls based on the stored address

• Syntax: return_type (*pointer_name)(parameter_types)

• Example: void (*funcPtr)(int) = &someFunction;
Answered by AI
Add your answer
Q4. What's polymorphism
Ans. 
Polymorphism is the ability of a function to behave differently based on the object it is called with.
• Polymorphism allows objects of different classes to be treated as objects of a common superclass.

• There are two types of polymorphism: compile-time (function overloading) and runtime (virtual functions).

• Example: A base class Animal with a virtual function 'makeSound'. Subclasses Dog and Cat override 'makeSound' to bark ...read more
Answered by AI
Add your answer
Q5. What's compile time polymorphism
Ans. 
Compile time polymorphism is achieved through function overloading and templates in C++.
• Compile time polymorphism allows for different functions to be called based on the arguments provided at compile time.

• Function overloading is a form of compile time polymorphism where multiple functions have the same name but different parameters.

• Templates in C++ allow for generic programming and compile time polymorphism by creatin...read more
Answered by AI
Add your answer
Q6. Question about default argument
Ans. 
Default arguments in C++ allow functions to be called with fewer arguments than defined, enhancing flexibility.
• Default arguments are specified in the function declaration, e.g., `void func(int x, int y = 10);`.

• If a default argument is provided, it can be omitted when calling the function, e.g., `func(5);` uses `y = 10`.

• Default arguments can be used for any data type, including user-defined types.

• They must be specified ...read more
Answered by AI
Add your answer
Q7. Overload + operator to add two complex numbers
Ans. 
Overload + operator to add two complex numbers in C++.
• Define a class for complex numbers with real and imaginary parts.

• Overload the + operator as a member function of the class.

• Return a new complex number with the sum of real and imaginary parts.
Answered by AI
Add your answer
Q8. Order of constructor and destructor. In case virtual function and about virtual destructor
Add your answer
Q9. Write stack which can work with any data type. Basically template
Ans. 
A template-based stack implementation in C++ that can handle any data type.
• Use templates to define a generic Stack class: `template <typename T>`.

• Implement basic stack operations: push, pop, and top.

• Use a dynamic array (or linked list) to store stack elements.

• Example: `Stack<int> intStack; intStack.push(5);`

• Example: `Stack<std::string> stringStack; stringStack.push("Hello");`
Answered by AI
Add your answer
Q10. Write code to delete node from linked list
Ans. 
To delete a node from a linked list, update the pointers of the previous node to skip the node to be deleted.
• Traverse the linked list to find the node to be deleted

• Update the pointers of the previous node to skip the node to be deleted

• Free the memory allocated to the node to be deleted
Answered by AI
Add your answer