80+ C Developer Interview Questions and Answers

Questions related to OOP concepts, pointers, memory allocation, PL SQL, and code snippets.

• OOP concepts include encapsulation, inheritance, and polymorphism.

• Pointers hold memory addresses, while references are aliases for existing variables.

• malloc() allocates memory on the heap, while new allocates memory on the heap and constructs an object.

• PL SQL is a procedural language used for managing data in Oracle databases.

• Code snippets can have varying outputs depending on the input ...read more

The puzzle involves stacking 4 tiers of different sizes with one spare tier. The task is to find the minimum number of moves to stack them all.

• Start by placing the largest tier at the bottom and the smallest at the top.

• Move the spare tier to the desired position to stack the next tier.

• Repeat until all tiers are stacked.

• The minimum number of moves required is 15.

To store 12 bytes of char in 6 bytes by reversing each byte, we can split the original bytes into pairs and reverse the order of each pair.

• Split the 12 bytes into 6 pairs of 2 bytes each

• Reverse the order of bytes in each pair

• Store the reversed pairs in the 6 bytes of memory

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};

Yes, I have used Windows API's extensively in my previous projects.

• I have used Windows API's for tasks such as creating windows, handling messages, and interacting with system resources.

• Examples include using functions like CreateWindow, SendMessage, and ReadFile.

• I have also worked with specific Windows API's like Winsock for networking and WinINet for internet-related tasks.

Stack memory is allocated automatically, while heap memory is allocated manually.

• Stack memory is limited and has a fixed size, while heap memory is larger and can grow dynamically.

• Stack memory is faster to access than heap memory.

• Stack memory is used for local variables and function calls, while heap memory is used for dynamic memory allocation.

• Examples of stack memory include function call stack and local variables, while examples of heap memory include dynamically allocated...read more

IPC stands for Inter-Process Communication, which allows processes to communicate and share data with each other.

• IPC enables processes to exchange data and information with each other.

• Common IPC mechanisms include pipes, message queues, shared memory, and sockets.

• Examples of IPC usage include communication between a parent and child process, or between different processes on a network.

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

Program to find the second largest element in an array

• Iterate through the array to find the largest element

• Then iterate again to find the second largest element

• Handle edge cases like empty array or array with only one element

The design pattern used in my project is the Observer pattern.

• Implemented to establish a one-to-many dependency between objects.

• Allows multiple objects to listen and react to changes in a subject.

• Promotes loose coupling between objects.

• Example: Used to notify multiple UI components when a data model changes.

I primarily use C++17, but I am familiar with earlier versions as well.

• I am comfortable working with features introduced in C++17 such as structured bindings and constexpr if

• I have experience with earlier versions like C++11 and C++14

• I stay updated with the latest features and improvements in C++ standards

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.

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

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 creating functions or classes that can work with any data type.

• Co...read more

Ordered maps maintain element order; unordered maps use hash tables for faster access without order.

• Ordered maps (std::map) store elements in a sorted order based on keys.

• Unordered maps (std::unordered_map) use hash tables for faster average access time.

• Example of ordered map: std::map<int, std::string> orderedMap; // elements sorted by key

• Example of unordered map: std::unordered_map<int, std::string> unorderedMap; // elements not sorted

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 important.

• Example: Protecting a shared variable in a multithreaded...read more

Multiprogramming involves running multiple programs on a single processor, while multitasking involves executing multiple tasks within a single program.

• Multiprogramming allows multiple programs to be loaded into memory and executed concurrently, while multitasking involves switching between multiple tasks within a single program.

• In multiprogramming, the operating system decides which program gets the processor's attention at any given time, while in multitasking, the program ...read more

Multi-programming involves running multiple programs on a single processor, while multi-tasking involves running multiple tasks within a single program.

• Multi-programming allows multiple programs to be loaded into memory and executed concurrently, switching between them to utilize processor time efficiently.

• Multi-tasking allows a single program to perform multiple tasks simultaneously, such as running multiple threads or processes within the program.

• Examples of multi-programmi...read more

Maximize profit by buying and selling stocks multiple times with given prices.

• You can buy and sell stocks multiple times.

• Profit is made by buying before selling.

• Example: Prices = [7, 1, 5, 3, 6, 4] -> Buy at 1, sell at 5, profit = 4.

• You can also buy at 3 and sell at 6 for additional profit.

• Total profit = 4 + 3 = 7.

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

The four pillars of OOP are encapsulation, inheritance, polymorphism, and abstraction, forming the foundation of object-oriented design.

• Encapsulation: Bundling data and methods that operate on the data within a single unit (class). Example: A class 'Car' with attributes like 'speed' and methods like 'accelerate()'.

• Inheritance: Mechanism to create a new class from an existing class, inheriting its properties and behaviors. Example: 'ElectricCar' inherits from 'Car'.

• Polymorphis...read more

Threads are lightweight processes within a program that can run concurrently, allowing for multitasking. Programs are sets of instructions executed by a computer.

• Threads are independent sequences of execution within a program.

• Threads share the same memory space and resources, allowing for efficient communication and data sharing.

• Programs are a collection of instructions that tell a computer how to perform a specific task.

• Programs can be written in various programming language...read more

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'

Find the number with the highest frequency in an array of strings.

• Create a map to store the frequency of each number in the array.

• Iterate through the array and update the frequency in the map.

• Find the number with the highest frequency in the map.

OOPs pillars are the four main principles of Object-Oriented Programming: Inheritance, Encapsulation, Abstraction, and Polymorphism.

• Inheritance: Allows a class to inherit properties and behavior from another class.

• Encapsulation: Bundling data and methods that operate on the data into a single unit.

• Abstraction: Hiding the complex implementation details and showing only the necessary features of an object.

• Polymorphism: Ability to present the same interface for different data ty...read more

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 from right to left; once a parameter has a default value, ...read more

Union in C++ is a data structure that allows storing different data types in the same memory location.

• Unions are similar to structures but all members share the same memory location.

• Only one member of a union can be accessed at a time.

• Unions are useful when you need to store different data types in the same memory space.

• Example: union MyUnion { int i; float f; };

• Example: MyUnion u; u.i = 10; // Accessing integer member of the union