Kyndryl Interview Questions and Answers

Arrow functions are a concise way to write functions in JavaScript.

• Arrow functions have a shorter syntax compared to regular functions.

• They do not have their own 'this' keyword, and instead inherit 'this' from the parent scope.

• Arrow functions are best suited for non-method functions, and cannot be used as constructors.

• Example: const add = (a, b) => a + b;

Reverse a linked list by changing the next pointers of each node to point to the previous node.

• Start with three pointers: current, prev, and next.

• Iterate through the linked list, updating the next pointers to point to the previous node.

• Update prev, current, and next pointers in each iteration until the end of the list is reached.

Runtime polymorphism is the ability of a subclass to override a method from its superclass during runtime.

• Runtime polymorphism is achieved through method overriding in object-oriented programming.

• It allows a subclass to provide a specific implementation of a method that is already defined in its superclass.

• The actual method called is determined by the type of object at runtime.

• Example: Animal class has a method 'makeSound', Dog subclass overrides it with 'bark', Cat subclass ...read more

Abstraction in OOP is the concept of hiding complex implementation details and showing only the necessary features to the outside world.

• Abstraction allows us to focus on what an object does rather than how it does it

• It helps in reducing complexity and improving maintainability of code

• Example: A car is an abstraction of various components like engine, wheels, etc. Users interact with the car without needing to know the internal workings

CTE stands for Common Table Expression in SQL, used to create temporary result sets that can be referenced within a SELECT, INSERT, UPDATE, or DELETE statement.

• CTEs improve readability and maintainability of complex queries

• CTEs can be recursive, allowing for hierarchical data querying

• CTEs are defined using the WITH keyword followed by the CTE name and query