Explain pure virtual functions, C/C++ Programming

Assignment Help:

Pure Virtual Functions

An abstract class is one, which is used just for deriving some other classes. No object of this class is declared and used in the program. Likewise, there are pure virtual functions which themselves won't be used. Consider the above example with some changes.

class Shape

                 {

                  public :

virtual void print() = 0; // Pure virtual

                             function

                 };

                class Triangle : public Shape

                 {

                  public :

void print()

 {

                cout << " I am a Triangle " << endl;

 }

 };

class  Circle : public Shape

                 {

                  public :

void print()

 {

                cout << " I am a  Circle " << endl;

 }

                 };

 

 

 

void main()

 {

  Shape S;

  Triangle T;

  Circle C;

 

                  Shape *ptr;

 

                                ptr = &T;

                                ptr -> print();

 

ptr = &C;

                                ptr -> print();

                }

 


Related Discussions:- Explain pure virtual functions

Explain nested classes, Nested Classes Many a times, it becomes essenti...

Nested Classes Many a times, it becomes essential to have a class contain properties of two other classes. One way is to explain a class within another - that is a class with m

Minimum shelf, At a shop of marbles, packs of marbles are prepared. Packets...

At a shop of marbles, packs of marbles are prepared. Packets are named A, B, C, D, E …….. All packets are kept in a VERTICAL SHELF in random order. Any numbers of packets with thes

Hw8, Asks the user for an integer. if the number is less than 21, ask them ...

Asks the user for an integer. if the number is less than 21, ask them for a number again; repeat this until you get a number bigger than 20. 20 is not an acceptable number. Once yo

Program of file data, Program of file data: FileData::FileData( ffblk&...

Program of file data: FileData::FileData( ffblk& blk ) :     fileName( blk.ff_name ),     fileDate( (blk.ff_fdate >> 5) & 0x000F,               blk.ff_fdate & 0x0001F

What are arrays, What are Arrays? Numerous applications require the pro...

What are Arrays? Numerous applications require the processing of multiple data items that have identical characteristics. In such circumstances it is frequently convenient to p

String comparision, how to compare one file with another file. comparison s...

how to compare one file with another file. comparison should be like first line of first file compare every line of second file until it gets a blank line starting from the top and

Algorithm, Write algorithms to implement the insertion and deletion operati...

Write algorithms to implement the insertion and deletion operations.

Write a program that takes the image, Write a program that takes the image ...

Write a program that takes the image tracks.jpg and finds Canny edges, and then finds lines in these edges using the Hough transform. The easiest way to do this is to take the prog

Write a c program to input three real numbers, Write a C program to input f...

Write a C program to input five numbers and print them out on a new line Write a C program to input three real numbers and print them out as follows:   The first variable is

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd