Altair Engineering Sde1 Interview Questions and Answers

Copy constructor creates a new object by copying the values of an existing object.

• Copy constructor is used to create a new object with the same values as an existing object.

• It is invoked when a new object is initialized with an existing object.

• It is used to avoid shallow copy and ensure deep copy of objects.

• Example: MyClass obj1; MyClass obj2 = obj1; //copy constructor called to create obj2

Shallow copy creates a new object with the same reference as the original, while deep copy creates a new object with a new reference.

• Shallow copy only copies the reference to the original object, so changes made to the copy will affect the original object.

• Deep copy creates a new object with a new reference, so changes made to the copy will not affect the original object.

• In Python, shallow copy can be made using the cop...read more

Vectors are dynamic arrays that allocate memory dynamically. They work by storing elements in contiguous memory locations.

• Vectors allocate memory dynamically and store elements in contiguous memory locations

• They can be resized dynamically as needed

• Accessing elements is done using an index, similar to arrays

• Inserting or deleting elements in the middle of a vector can be expensive as it requires shifting all subsequent e...read more

STL provides various containers like vector, list, map, set, etc.

• Vector: Dynamic array with contiguous memory allocation

• List: Doubly linked list

• Map: Associative container with key-value pairs

• Set: Associative container with unique keys

• Deque: Double-ended queue

• Stack: LIFO data structure

• Queue: FIFO data structure

Ordered map maintains the order of insertion while unordered map does not.

• Ordered map is implemented using a balanced binary search tree while unordered map is implemented using a hash table.

• Ordered map is useful when we need to maintain the order of insertion while unordered map is useful when we need faster access to elements.

• Example of ordered map: std::map in C++, Example of unordered map: std::unordered_map in C++

Polymorphism is the ability of an object to take on many forms. It allows objects of different classes to be treated as if they were the same type.

• Polymorphism is achieved through method overriding and method overloading.

• Method overriding is when a subclass provides a specific implementation of a method that is already provided by its parent class.

• Method overloading is when a class has two or more methods with the same...read more

Name mangling is used by compilers to differentiate between different functions with the same signature.

• Name mangling is a process of encoding/decoding function names to include additional information such as parameter types and namespaces.

• This allows the compiler to differentiate between functions with the same name and signature.

• For example, in C++, two functions with the same name and signature but in different name...read more

C++ program to find absolute difference between sum of diagonal elements

• Create a 2D array

• Calculate sum of diagonal elements

• Calculate absolute difference

• Print the result

Virtual functions allow dynamic binding of functions at runtime. Vptr and Vtable are used to implement this feature.

• Virtual functions are declared in base class and can be overridden in derived classes.

• Vptr is a pointer to Vtable which contains addresses of virtual functions.

• Virtual function is needed to achieve polymorphism and to allow derived classes to have their own implementation of a function.

• Virtual functions a...read more

I am a software engineer with 5 years of experience in developing web applications and mobile apps.

• Developed a web application for a healthcare company using React and Node.js

• Built a mobile app for a retail company using React Native

• Worked on a project for a financial institution using Java and Spring Framework

• Experience in Agile methodology and Scrum framework

• Strong skills in problem-solving and debugging

Memory leaks occur when allocated memory is not released, leading to resource exhaustion. Proper management is essential.

• Use smart pointers (e.g., std::unique_ptr, std::shared_ptr) in C++ to automatically manage memory.

• In Java, ensure that references to unused objects are set to null to allow garbage collection.

• Regularly use tools like Valgrind to detect memory leaks in C/C++ applications.

• In languages like Python, use ...read more

Virtual functions enable polymorphism in C++, allowing derived classes to override base class methods.

• Without virtual keyword: Base class method is called, even if derived class method exists.

• With virtual keyword: Derived class method is called, enabling dynamic binding.

• Example without virtual: Base class method 'show()' is called from a base class pointer.

• Example with virtual: Derived class method 'show()' is called f...read more

Check if a point is inside or outside a circle

• Calculate the distance between the center of the circle and the given point using the distance formula

• If the distance is less than the radius of the circle, the point is inside the circle

• If the distance is equal to the radius of the circle, the point is on the circle

• If the distance is greater than the radius of the circle, the point is outside the circle

Smart pointers are objects that manage the memory of dynamically allocated objects, preventing memory leaks and dangling pointers.

• Smart pointers are a type of RAII (Resource Acquisition Is Initialization) technique.

• They automatically delete the object they point to when it is no longer needed.

• Examples of smart pointers include unique_ptr, shared_ptr, and weak_ptr in C++.

• They are used to prevent memory leaks and danglin...read more