Cognizant Core Knowledge and Fundamentals 2

Question 1

Which data structure uses LIFO (Last In, First Out) order?

Accepted Answer

Stack

Answer

A stack operates on LIFO principle where the last element added is the first to be removed.

Question 2

What is the time complexity of binary search on a sorted array of n elements?

Accepted Answer

O(log n)

Answer

Binary search halves the search space each iteration, resulting in O(log n) time complexity.

Question 3

In object-oriented programming, which concept allows a subclass to provide a specific implementation of a method already defined in its superclass?

Accepted Answer

Overriding

Answer

Method overriding allows a subclass to redefine a method from its parent class with its own implementation.

Question 4

Which SQL clause is used to filter results after a GROUP BY operation?

Accepted Answer

HAVING

Answer

The HAVING clause filters groups created by GROUP BY, whereas WHERE filters individual rows before grouping.

Question 5

What does the OSI model's Transport layer primarily handle?

Accepted Answer

End-to-end communication and error recovery

Answer

The Transport layer (Layer 4) is responsible for end-to-end communication, flow control, and error recovery using protocols like TCP and UDP.

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