Skip to main content

Classes and Structures in C++

In C, a structure (struct) gives us the ability to organize similar data together. You may wonder what I said. It is so in C, this is because structure is one of the few things which is more or less entirely different in the two languages (C and C++).

In C++, the role of structures is elevated so much as to be same as that of a class. In C, structure could only include data as variables and arrays but in C++ they can also include functions, constructors, destructors etc. and in fact everything else that a class can. Knowing this, it wouldn’t be wrong to say that in C++, structures are an alternate way of defining a class. However there are some differences.

Look at the following code:


  // First difference between a class
  // and a structure in C++
   
  // define a structure
  struct mystruct
  {
    char name[25];
    int id_no;
  };

  void main()
  {
    mystruct a;
    // in C, it is necessary to
    // include the struct keyword

    // Example:
    // struct mystruct a;

    ...
    ...
    ...
  }

In C, we must declare an object of a structure by using the keyword struct but in C++ it is optional to do so (just like a class).

Another difference is the fact that all the data or functions inside a struct are public by default contrary to a class, inside which scope is private by default.

It is obvious from the following code:


  // Second difference between a class
  // and a structure in C++

  // define a structure
  struct mystruct
  {
    // public by default
    // So convenient to start with
    // public declarations

    void func1();
    void func2();
    ...
    ...

  private:
  // now private
    int data1;
    int data2;
    ...
    ...
  };

  // define a class
  class myclass
  {
    // private by default
    int data1;
    int data2;
    ...
    ...

  public:
  // now public
    void func1();
    void func2();
    ...
    ...
  };

While you’ve got the power, you should not define a class as a struct since it is not a good practice. Structures and classes should be used as per their original purposes to avoid unnecessary complications and misunderstandings.

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

Designing a Simple Order Form Application in PHP

Ok guys, for this post we’re going to create a simple yet complete order form page. Order forms are used on many sites to take customers order online. Order forms should have the capability to take orders from visitors regarding what items they want to purchase and store the information for further processing. For this post’s example, we are going to create an order form for a Book Seller. The form will be designed to take order of five different items (books). Our order form application should be able to take order of five different items in any separate quantities tht user wants, it should also ask for shipping address and name of the customer. It should then store the information provided in a file along with the date and time order was placed. The application should also be able to take any number of orders and store them all linearly for further human processing. For this, we need a front end of a HTML form to which the user would interact a