Compound Types

 There are 2 compound data types in PHP.

1.   Array

2.   Object

Array:

The array is a collection of heterogeneous (dissimilar) data types. PHP is a loosely typed language that?s why we can store any type of values in arrays.

Normal variable can store single value, array can store multiple values.

The array contains a number of elements, and each element is a combination of element key and element value.

SYNTAX OF ARRAY DECLARATION:

Variable_name = array (element1, element2, element3, element4......)  

Example 1

<?php  
    $arr= array(10,20,30);  
    print_r($arr);  
?>  

Example 2

<?php  
    $arr= array(10,'sonoo',30);  
    print_r($arr);  
?>  

Example 3

<?php  
    $arr= array(0=>10,2=>'sonoo',3=>30);  
    print_r($arr);  
?>  

Object:

An object is a data type which accumulates data and information on how to process that data. An object is a specific instance of a class which delivers as templates for objects.

SYNTAX:

At first, we must declare a class of object. A class is a structure which consists of properties and methods. Classes are specified with the class keyword. We specify the data type in the object class, and then we use the data type in instances of that class.

Example 1

<?php class vehicle  
    {  
        function car()  
        {           
        echo "Display tata motors";  
        }  
    }  
    $obj1 = new vehicle;  
    $obj1->car();   
?>  

Example 2

<?php  
    class student   
    {  
            function student()   
        {  
                $this->kundan = 100;  
            }  
    }     
    $obj = new student();  
    echo $obj->kundan;  
?>  

Example 3

<?php  
    class greeting  
    {  
    public $str = "Hello skyapper and SSSIT";  
        function show_greeting()  
        {  
                return $this->str;  
            }  
    }  
    $obj = new greeting;  
    var_dump($obj);  
?>