Cognizant Software Developer Interview Questions and Answers for Freshers

Create a class Person with private variables name and age, and methods to set and get their values.

• Create a class Person with private variables 'name' and 'age'.

• Implement a method setValue to set the variables' values.

• Implement a method getValue to print the variables' values.

• Ensure the name is a non-empty string and the age is a non-negative integer.

• Encapsulate the data and provide a clear interface for setting and getting the values.

Implement a function to encode a text message using run-length encoding.

• Iterate through the message and count consecutive characters

• Append the character and its count to the encoded message

• Handle edge cases like single characters or empty message

Hashtable is synchronized and does not allow null keys, while hashmap is not synchronized and allows one null key.

• Hashtable is synchronized, while hashmap is not.

• Hashtable does not allow null keys, while hashmap allows one null key.

• Hashtable is thread-safe, while hashmap is not.

• Hashtable is slower than hashmap.

• Hashtable is part of the legacy collection classes, while hashmap is part of the Java Collections Framework.

Virtual function is a function in base class that is overridden in derived class.

• Virtual functions allow polymorphism in C++

• They are declared using the virtual keyword

• They are resolved at runtime based on the object type

• Virtual functions can be overridden in derived classes

• They are used to achieve runtime polymorphism

An array is a data structure that stores a collection of elements of the same type in a contiguous memory location.

• Arrays are used to store multiple values in a single variable.

• Elements in an array are accessed by their index, starting from 0.

• Example: string[] names = {"Alice", "Bob", "Charlie"};

• Arrays can be used to efficiently store and retrieve data in programming.

• Arrays can be multidimensional, allowing for more complex data structures.

A linked list is a data structure that consists of a sequence of elements where each element points to the next element in the sequence.

• Each element in a linked list is called a node.

• Nodes in a linked list are connected by pointers or references.

• Linked lists can be singly linked (each node points to the next node) or doubly linked (each node points to the next and previous nodes).