Virtual characteristic in c++ is a member feature described inside the base magnificence which you may redefine inside the derived class. So if in the programming you want to consult an item of the derived class using the reference of the bottom magnificence or pointer you can use the virtual characteristic for calling that item and then you could execute the characteristic of the derived class. A digital keyword is used to outline a virtual characteristic inside the programming. To reap runtime polymorphism within the software programs digital features are used. The characteristic name could be resolved at runtime simplest.

Here is the syntax for defining a virtual function in C + + programming language:

Virtual is the mandatory keyword to be used before function name then function name that can be anything of user choice.

Some important rules to keep in mind while using and working with virtual functions in the C + + programming language:

A class cannot have a virtual constructor in the code but the same class can have a virtual destructor in the code.

Data type or we call it the prototype of the virtual function defined in the program must be the same in both the base class and derived class.

The most important rule about virtual functions is that they must be defined in the base class only and must be overridden through the derived class.

To achieve run time polymorphism in your code you must access virtual function through either pointer or the base class reference.

The compiler does two things whenever there is a virtual function mentioned in the class of any given program:

If a class contains a virtual function then the compiler itself does two things:

The compiler will insert a virtual pointer (VPTR) as a data member of the class if an object of that class is created to point at the VTABLE of that particular class. Therefore, the compiler will do this every time a new object is created so that the new virtual pointer will be inserted as a data member of the class.

Another thing compiler will do is that even if the object is not created a static array of the function pointer will call VTABLE in which each table cell will contain the address of every virtual function defined in that class.

As we have seen the syntax and working of virtual function now we will see how it works when we implement it in the code:

Here is the C + + code to demonstrate the working example of the virtual function in the C + + programming language.

{ cout << " Loading Automobile functionalities. \n " ; }

{ this -> Automobile :: functionalities();

cout << " Loading wheel functionalities. \n" ;

this -> Automobile :: functionalities () ;

cout << " Loading glass functionalities. \n" ;

void loadfunctionalities ( Automobile *Automobile )

Here is the C ++ code to demonstrate the working example of the virtual function in the C++ programming language.

Let's start the discussion with Virtual Functions in C++

Works & Examples of Virtual Functions in C++

This C++ begin() is used to get the iterator pointing to the initial element of the map container. This pointer is bidirectional since it can be moved to either direction in the sequence. This function is present in map associative container class template in std namespace where elements are stored in the form of key-value pairs. Here keys are used to uniquely identify the values of the elements and also the elements are stored in sorted order where keys are the sorting criteria. The function requires no arguments thus is called directly using map container reference and provides a guarantee of no exception when the correct syntax is followed.

Map are associative containers that store the elements in key-value pair fashion, such that no 2 elements can have 2 same keys. This contains begin() function that gives a bidirectional iterator pointing to the first element of the container.

Parameters- No parameter is required for calling begin function just map reference object is used to directly call this function using dot(.) operator.

Explanation: Here iterator and const_iterator are two different types of iterator that are returned according to the reference of the map object calling the function.

Iterator – In case the map object is not cons-qualified then member -types iterator is returned. This is a bidirectional iterator that points to the first element of the map container, and here element refers to the key-value pair.

Const_iterator – In case map reference is const-qualified then a bidirectional const-iterator is returned pointing to the first element of the cont map container and here key-value pair is referred to as an element.

The map is an associative container that stores the elements in key-value pairs in a sorted manner where elements are sorted by the key values. Here begin function helps to get an iterator pointing to the first element of the container and helps to traverse through all the elements stored in the container.

When a map says:- map<datatype1, datatype1> map object; is declared where datatype1 and datatype2 are datatypes of key and values of map reference map object. If one needs to traverse the elements in the given map, one needs an iterator. Thus when one call begin to function-

it is checked if map reference is const-qualified or not and depending on that corresponding function is called and returns the const_iterator or iterator respectively. For calling begin function no parameter is required. The returned iterator is also of map function type in key-value pair form. The returned iterator is a bidirectional iterator that means one can traverse the elements in forwarding as well as the backward direction that helps to traverse elements in reverse order easily. This function is present in the std template of a map in the Standard Template Library. It guarantees that no exception will be thrown while calling it, even if there is no element in the map. One must note that the returned iterator object must not be dereferenced.

Let us see an example of a map to store percentages of students in a class against their roll numbers. To print their values we need an iterator to traverse over all the elements in the map. This iterator is retrieved using class10.begin() function and stored in reference variable it and traversed until end of the map is reached and iterator points to an element being pointed by map. end() function. Elements from it are accessed using its->first and it->Second statements.

map<int, int> class10; //map declaration of key-value pair of int-int type

map<int, int>::iterator itr;  // iterator of int-int  type

cout << "\nThe map of percentages of students of  class10 is : \n";

for (itr = class10.begin(); itr != class10.end(); ++itr) {

In this example, we will try to access an iterator over an empty map and see no error or exception is thrown, but nothing is printed.

Let's see one example if we insert elements in unsorted order. We will see map will sort the elements according to the key values i.e roll_no since the map stores the elements in sorted order only, and then values are traversed and will be printed.

map<int, string>::const_iterator myIterator;

myIterator = Student.begin();  //iterator to first element is returned

cout << "ROLL_NO"<<"\t" <<"NAME" << "\n";

cout << myIterator->first <<"\t"  << myIterator->second << "\n";

In this blog, we will discuss Works of begin() in C++

Works of begin() in C++

The std::size( ) function returns the size of the given variable, container or an array. The std::size( ) function  is a built in function in the C++ STL (Standard Template Library). The std::size( )function is available if any of the headers are included like <array>, <set>, <list>, <map>, <string>, <deque>, <forward_list>, <regex>, <vector>, <string_view>, <unordered_map>, <unordered_set> etc and hence the std::size( ) function can be apply to all these variables, containers or arrays.

template< class T, std::size_t N >constexpstd::size_t size(const T (&a)[N]) noexcept

Where a is the variable or container or an array that stores some value. The function returns the size of the variable or container or array.

Implementation of size( ) function in C++ SLT

Lets see the latest implantation version that is c++ 11 version of std::size( ) function as below:

constexpstd::size_t size( const T (&a)[N]) noexcept

As in above code the size(const T (&a)[N] )  function is call by reference. The references stores the address of pass variable and directly referencing variable and processing directly to them and returns the size of the variable passes. C++ overloading size( ) function to  std::size_t size( const T (&a)[N] ).

Examples to Implement size( ) function in C++

We write the c++ code to understand the size( ) function more clearly with the following example where we use the size( ) function to get the size of a string variable, as below:

string s = "Get the size of this string";

cout<< "The size of the given string is = " << n;

cout<< "Initial size of the vector = " <<v.size() << '\n';

cout<< "After insert an elements the size of the vector = " <<v.size() << '\n';

cout<< "After pop an elements the size of the vector =  " <<v.size() <<endl;

cout<< "Initial size of the list = " <<l.size() << '\n';

cout<< "After insert an elements the size of the list = " <<l.size() << '\n';

cout<< "After pop an elements the size of the list =  " <<l.size() <<endl;

cout<< "Initial size of the set = " <<s.size() <<endl;

cout<< "After insert an elements the size of the set = " <<s.size() << '\n';

cout<< "After pop an elements the size of the set =  " <<s.size() << '\n';

cout<< "The size of the array is  = " <<a.size() <<endl;

Let's start the discussion with Implementation of size( ) function in C++

Implementation of size( ) function in C++

The test() function in C++ is used to test whether in a bit string at the specified index the bit is set or now not. The test() function is a built-in function in C++ which is defined in the <bits/stdc++.h> or <bitset> header file, this header file includes every standard library. The text() function accepts the handiest one parameter which is the index role of the bit string, at that index function if the bit is one then the function returns authentic, otherwise returns false if the bit is zero.

The test() function is used or known as on the bitset string(a set of 0’s and 1’s stores in the string layout) to locate at a selected index function in a piece string whether the bit is set(1) or not set(0), so the take a look at() function accepts best one parameter that is the index function of the bit string and checks for that index function in a piece string the bit is 1 or 0. If the bit keep is 1 then returns authentic, else returns false if the bit is 0, as we will see in the underneath examples.

Examples to Implement of test() Function in C++

Below are the examples of the test() function:

We write the C++ code to understand the test() function more clearly with the following example where we use the test() function to check all the bits of the bit string, as below:

// code to check all the bits whether set or not

cout << "The bit at index "<< i << " is "<< bstr.test(i) << endl;

We write the C++ code to understand the test() function where we use the test() function to check the user given bit index of the bit string, as below:

cout<<"Enter the bit index, which you want to test :";

// code to check whether the bit at given index is set or not

cout << "The bit at given index "<< index << " is "<< bstr.test(index) << endl;

We write the C++ code to understand the test() function where we use the test () function to check the user given bit index whether set or not, as below:

cout << "The bitset is set at index " << index;

cout << "The bitset is not set at index " << index;

We write the C++ code to understand the test() function where we use the test() function to compare two different strings, as below:

// code to check whether the two bit strings are equal or not

cout<< "Both the bit strings are equal.";

cout<< "Both the bit strings are not equal.";

In this blog, we will discuss the Working of the test() function in C++

Works of test() function in C++

Bitset is one of the important training within the c++ library that enables to emulate strings or numbers inside the shape of a chain of bits stored like an array in which each of the bits is saved at consecutive positions inside the array. For the reason that the garage dataset used is an array, every bit may be referenced using a selected index that helps within the fast get entry to of factors. Any() method is one of the strategies supplied in bitset elegance to locate if any of the bits present in the array is ready this is its value is ‘1’. If not one of the bits is set false is returned.

This method requires no parameters to be passed while calling. Only the reference to one of the objects of the Bitset class calls this method for the bitset representation object is holding.

Bool: Determines that the return type for this method is a Boolean, that is either true in case any one of the bit is set otherwise false.

Const: restricts any changes to this method by any of its child classes.

After C++11 this method does not throw any exception, can be inferred using the noexcept keyword mentioned in its declaration.

A bitset helps to emulate an array of bool where each bit is stored in such a way to use memory efficiently as memory consumed to store a bitset is far less than the storage of Boolean array or vector. Thus it can be inferred the information stored using bitset is stored in a compressed manner, thus helping in enhancing the performance of the array and vector operations on it. The only limitation of using bitset is the size of the array needs to be declared at compile time.

Each bit in the bitset array can easily be accessed using indexes for eg, obj[3] points to the element stored at index 3 in the bitset from the right side.

Bitset also gives a constructor to get the bitset representation of given string and numbers. Thus one can easily use this class to store the information. It provides various methods to perform operations on the bits such as:-

When Any() method is triggered for a bitset object, the compiler traverses the whole array of bitset from 0 to N index, where N is declared at compile-time, and checks if the bit is set i.e the value of the bit at that index is 1. If yes it breaks the loop and returns true Boolean otherwise False Boolean. Any() method working is the same as the loop given below:-

All the bitwise operations on the bitset can be performed without any type of conversion or casting, which helps enhance the performance and efficiency.

Main overloaded methods are &,!,==,!= also <> shifting operators. And Any() method can be used to detect if the given number contains any set bit to perform these operations otherwise ignore the bitset directly.

Examples to Implement of C++ any() Function

Let us consider one simple example to understand how any function in bitset works.

cout << obj1 << " has one of its bits set"

cout <<  " None of the bits is set in "<< obj1

cout << obj2 << "  has one of its bits set"

cout << "None of the bits is set in " << obj2

In the second example, we will see the working of any function for 4 different bitset objects.

cout << "Bitset representation of uninitialised obj1 is " <<obj1 << endl;

cout << "Bitset representation of 16 is " <<obj2 << endl;

cout << "Bitset representation of \"00010\" is " <<obj3 << endl;

cout << "Bitset representation of array with 2nd 3rd bbits set is "<< bitarr << endl;

cout << "Lets check if any of the bit is set in above 4 bitset representations: ";

if( obj1.any()) cout<< "obj1: " <<"TRUE"<<endl ;else cout << "FALSE" <<endl;

if( obj2.any()) cout<< "obj2: " <<"TRUE"<<endl ;else cout <<"FALSE" <<endl;

if( obj3.any()) cout<< "obj3: " <<"TRUE" <<endl;else cout<<  "FALSE" <<endl;

if( bitarr.any()) cout<< "bitarr: " <<"TRUE"<<endl; else  cout<< "FALSE" <<endl;

Let's start this blog with any() function in C++

Works & Advantages of any() function in C++

C++ bitset is a very good optimization technique for the set of boolean values represented with the help of array bools. This special set of boolean values includes values in the format of true or fake. If the cost is proper, then it's miles representing that the array bool set includes fee as 1 which indicates that it occupies the unit bit area of 1 bit. If the array bool values encompass a fee as false which means illustration is with fee 0 which means the bit is unsaved for transition and changes.

This function is part of C++ Bitset which is used for testing and verifying whether all the bits are set properly or not.

Example: This program demonstrates bitsetall() function for the setting of every bit in the set.

cout << "Let us set all the bits repectively" << endl;

cout << "Every single bit set is ready for execution and can be overriden as well." << endl;

This function is used by the  C++ bitset library function to set at least one bit of the stream. If not set it will not return the actual value which is needed.

Example: This program demonstrates that the bitset::any() function is used for at least set one value for the function.

cout << "Minimum of one single bit needs to get set in the array" << endl;

cout << "Any one single or minimum one bit should get set." << endl;

As the name suggests this bitset::count function is also part of the bitset standard library which is used to count the number of bits present in the bitset.

Example: This program is to illustrate the bitset::count function for keeping track and checking on the count of the number of bits occupying the bit and space compared with the bits apart from the set of bits that don’t have values.

cout << "Given Bitset " << k << ", " << k.count() << " possess number of set bits" << endl;

bitset::flip function is used to represent the set of bit characters that toggles between the entire bitstream.

Example: This program is used to represent the bitset::flip() function which is used to represent the bits in order like the bits before calling a flip() function and bit representation after calling a flip() function.

cout << " bits pattern before performing a flip = " << m << endl;

cout << " bits representation after performing a flip = " << m << endl;

This function is also part of the C++ bitset stream library which is further used to test whether all the bits are properly set or kept as unset and it can be confirmed seamlessly by making use of this function.

Example: This program illustrates the function bitset::none () to represent whether all the bits are set or all the bits are unset.

cout << "Ths function tests result whether all the bits are set or unset" << endl;

cout << "Minimum one bit shoud get set among all the unset bits" << endl;

Today we will start the discussion on Bitset.

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