C++ Template Interview Preparation Guide

A class is a user defined data type. It serves as a template of the objects. You can define structure and behavior of an object using class. It includes data and the member functions that operate on data.

Inheritance enables a new class to reuse the state and behavior of old class. The new class inherits properties and methods from the old class and is called as derived class and the old class is called as base class. The methods thus inherited can be extended using overriding facility of C++.

The wrapping up of data and member function into an object is called encapsulation. The data is not accessible to the outside world and only those functions which are wrapped into the object can access it. An encapsulated objects act as a "black box" for other parts of the program which interact with it. They provide a service, but the calling objects do not need to know the details how the service is accomplished.

Polymorphism enables one common interface for many implementations, and for objects to act differently under different circumstances. You can also achieve polymorphism in C++ by function overloading, operator overloading and implementation inheritance.

Object
Class
Data Abstraction and Encapsulation
Polymorphism
Inheritance
Message passing
Dynamic binding

Some key features of the Object Oriented programming are:

Emphasis on data rather than procedure
Programs are divided into entities known as objects
Data Structures are designed such that they characterize objects
Functions that operate on data of an object are tied together in data structures
Data is hidden and cannot be accessed by external functions
Objects communicate with each other through functions
New data and functions can be easily added whenever necessary
Follows bottom up design in program design

Templates is one of the features of C++. Using templates, C++ provides a support for generic programming.

We can define a template for a function that can help us create multiple versions for different data types.

A function template is similar to a class template and it syntax is as follows:
template <class T>
Return-type functionName (arguments of type T)
{
//Body of function with type T wherever appropriate
}

A class holds the data and functions that operate on the data. It serves as the template of an object.

The Standard Template Library, or STL, is a C++ library of container classes, algorithms, and iterators; it provides many of the basic algorithms and data structures

The STL includes the classes vector, list, deque, set, multiset, map, multimap, hash_set, hash_multiset, hash_map, and hash_multimap.

The life of a static data member exists between the functions which means that they are resident through out the execution of a program like the global variables.