Skip to main content

Practical Example of Using Virtual Functions II

From the past few articles we have been discussing about Virtual Functions. Before taking up another topic for discussion I thought of providing one more example of how and when virtual functions may be used. So, here it is, a practical example of virtual function.

As virtual functions and Run-Time Polymorphism goes hand-in-hand so the example here may also serve as an example of the use of run-time polymorphism.


  // Example to illustrate
  // the use of virtual functions
  // and run-time polymorphism
  #include <iostream.h>

  // -- SORT CLASS --
  class sort
  {
  protected:
    int *arr;
    int num_elmnt;

  public:
    sort(int);
    ~sort();
    void get_elmnt();
    void show_elmnt();
    virtual void do_sorting()=0;
  };

  // takes an argument
  // which is the number of
  // elements we want
  sort::sort(int x)
  {
    num_elmnt=x;
    arr=new int[num_elmnt];
  }

  sort::~sort()
  {
    // free up he allocated memory
    delete []arr;
  }

  void sort::get_elmnt()
  {
    // input elements
    cout<<"\nEnter Elements...";
    for(int i=0;i<num_elmnt;i++)
    {
      cout<<"\n#"<<i+1<<":";
      cin>>arr[i];
    }
  }

  void sort::show_elmnt()
  {
    // display the elements
    cout<<"\nElements are...";
    for(int i=0;i<num_elmnt;i++)
    {
      cout<<"\n#"<<i+1<<":";
      cout<<arr[i];
    }
  }
  // -- SORT CLASS ENDS --

  // -- BUBBLE SORT CLASS --
  class bubble_sort : public sort
  {
  public:
    // constructor only calls the 
    // base constructor with the
    // parameter
    bubble_sort(int x):sort(x){}

    void do_sorting();
  };

  void bubble_sort::do_sorting()
  {
    int temp;

    // do bubble sorting
    for(int i=0;i<num_elmnt;i++)
      for(int j=0; j<(num_elmnt-1); j++)
        if (arr[j]>arr[j+1])
        {
          temp=arr[j];
          arr[j]=arr[j+1];
          arr[j+1]=temp;
        }
  }
  // -- BUBBLE SORT CLASS ENDS --

  // -- SELECTION SORT CLASS --
  class selctn_sort : public sort
  {
  public:
    // just call the base class
    // constructor
    selctn_sort(int x):sort(x){}
    void do_sorting();
  };

  void selctn_sort::do_sorting()
  {
    int temp;

    // do selection sorting
    for(int i=0;i<(num_elmnt-1);i++)
      for(int j=i+1;j<num_elmnt;j++)
      {
        if(arr[i]>arr[j])
        {
          temp=arr[i];
          arr[i]=arr[j];
          arr[j]=temp;
        }
      }
  };
  // -- SELECTION SORT CLASS ENDS --

  void main()
  {
    bubble_sort bubble(3);
    selctn_sort selctn(5);
    sort *ptr;

    ptr=&bubble;
    ptr->get_elmnt();
    ptr->do_sorting();

    ptr=&selctn;
    ptr->get_elmnt();
    ptr->do_sorting();

    // again point to bubble
    ptr=&bubble;
    ptr->show_elmnt();

    // again point to selctn
    ptr=&selctn;
    ptr->show_elmnt();
  }

Related Articles:

Popular posts from this blog

Fix For Toshiba Satellite "RTC Battery is Low" Error (with Pictures)

RTC Battery is Low Error on a Toshiba Satellite laptop "RTC Battery is Low..." An error message flashing while you try to boot your laptop is enough to panic many people. But worry not! "RTC Battery" stands for Real-Time Clock battery which almost all laptops and PCs have on their motherboard to power the clock and sometimes to also keep the CMOS settings from getting erased while the system is switched off.  It is not uncommon for these batteries to last for years before requiring a replacement as the clock consumes very less power. And contrary to what some people tell you - they are not rechargeable or getting charged while your computer or laptop is running. In this article, we'll learn everything about RTC batteries and how to fix the error on your Toshiba Satellite laptop. What is an RTC Battery? RTC or CMOS batteries are small coin-shaped lithium batteries with a 3-volts output. Most laptops use

The Best Way(s) to Comment out PHP/HTML Code

PHP supports various styles of comments. Please check the following example: <?php // Single line comment code (); # Single line Comment code2 (); /* Multi Line comment code(); The code inside doesn't run */ // /* This doesn NOT start a multi-line comment block /* Multi line comment block The following line still ends the multi-line comment block //*/ The " # " comment style, though, is rarely used. Do note, in the example, that anything (even a multi-block comment /* ) after a " // " or " # " is a comment, and /* */ around any single-line comment overrides it. This information will come in handy when we learn about some neat tricks next. Comment out PHP Code Blocks Check the following code <?php //* Toggle line if ( 1 ) {      // } else {      // } //*/ //* Toggle line if ( 2 ) {      // } else {      // } //*/ Now see how easy it is to toggle a part of PHP code by just removing or adding a single " / " from th

How to Create an HTML Form Linked with MySQL Database in PHP

If you're looking for example code and detailed discussion on how to create an HTML form that stores data in a MySQL database using PHP then this post might be what you're looking for. I assume that you're familiar with basic HTML, CSS, PHP coding, and  MySQL. I am going to divide this small project into two parts: The HTML form itself that takes input from the user and the PHP script that saves it into the database A table that displays the user-added data that has been saved in the database. We'll be dealing with the first part in this tutorial. Again I'd like to break this problem into a few parts so that it's easier for you to understand and probably gives you an insight into how breaking up a problem into smaller chunks can help make things clearer in your mind. Let's think about it, there is an HTML form (that is HTML code), then there is the PHP code that deals with the user-input data, and the MySQL database itself. For this tutorial, we'll b