Interview Questions and Answers

Join is used to combine rows from two or more tables based on a related column between them.

• Types of joins include inner join, outer join (left, right, full), cross join, self join.

• Inner join returns rows when there is at least one match in both tables.

• Outer join returns all rows from one table and matching rows from the other table.

• Cross join returns the Cartesian product of the two tables.

• Self join is used to join a table to itself.

Program to reverse an array of strings in C

• Declare an array of strings

• Use a loop to swap elements from start to end

• Print the reversed array

Program to reverse a string in C

• Use a loop to iterate through the characters of the string

• Swap the characters from start to end of the string

• Continue swapping until reaching the middle of the string

A friendly function is a function that is not a member of a class but has access to the private and protected members of the class.

• A friendly function is declared with the keyword 'friend' in the class that it is granting access to.

• It can access private and protected members of the class it is declared as a friend of.

• It is not a member of the class itself, but can be defined outside of the class.

• Example: class A { private: int x; friend void display(A obj) { cout << obj.x; } ...read more

Inheritance is a concept in object-oriented programming where a class inherits properties and behaviors from another class.

• Allows a class to inherit attributes and methods from another class

• Promotes code reusability and reduces redundancy

• Supports the concept of parent and child classes

• Derived class can override methods from the base class

• Example: Class 'Car' can inherit from class 'Vehicle'

Oops concepts are the principles of Object Oriented Programming, including Inheritance, Encapsulation, Polymorphism, and Abstraction.

• 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.

• Polymorphism: Ability to present the same interface for different data types.

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

Encapsulation, Inheritance, Polymorphism, Abstraction are the 4 pillars of OOP.

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

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

• Polymorphism: Ability for objects to be treated as instances of their parent class.

• Abstraction: Hides the complex implementation details and only shows the necessary features.