How to use classes?

Question

I am new to programming, and there is one thing that I confused. What is a class and how to use it? I understand a little, but I can not find the full answer.

By the way, if it depends on the language, then I program in PHP.

Edit: There's something else I forgot to say. In particular, I wanted to ask how defining functions are used in classes. I saw examples of PHP code where functions are defined inside classes, but I cannot understand why.

Answer 1

As concise as possible: a class describes a dataset that can perform actions on its own.

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Answer 2

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Answer 3

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class person
{
   $gender = null;
   $weight = null;
   $height = null;
   $age = null;
   $firstName = null;
   $lastName = null;
   function __CONSTRUCT($firstName, $lastName)
   {
      //__CONSTRUCT is a special method that is called when the class is initialized
      $this->firstName = $firstName;
      $this->lastName = $lastName;
   }
}

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$steve = new person('Steve', 'Jobs');

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$steve->age = 54;

Answer 4

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Answer 5

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Answer 6

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CarClass theCar = new CarClass(); //

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CarClass theCar = new CarClass(); //In a way this says this word "car" will be a car
theCar.Color = red; //Given the instance of a car we can add that color detail.

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Answer 7

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http://ficl.sourceforge.net/oo_in_c.html

Answer 8

, http://www.cplusplus.com/doc/tutorial/

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Answer 9

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Answer 10

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• Exports a certain correct behavior: a description of the classes follows;

Instantiation:

• A way to instantiate a class to create an object;
• Returns the object in a valid state;
• Performed by the constructor;

To use a class, you must create an instance of the class, although this will be a contructor. In PHP, a simple example could be:

<?php
class SampleClass {
   function __construct() {
       print "In SampleClass constructor\n";
   }
}

// In SampleClass constructor
$obj = new SampleClass ();
?>