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Objects in PHP

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• Defining a Class in PHP
  • Syntax to define a class:

    class objTypeName { public $var1; // Public variables public $var2; // (You can use private too; but I like public... ... }

    Example:

    class myObject { public $name; public $bal; }

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• Defining object variables
  • Syntax to define a (class) object variable:

    $varName = new objTypeName( );

    Example:

    $john = new myObject();

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• Using object variables
  • Access a field in an object:

    $objVar->fieldName

    Example:

    $john = new myObject(); $john->name = "John Smith"; $john->bal = 40000; print($john->name . "\n"); print($john->bal) . "\n";

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• A special print function for objects
  • print_r():

    print_r( $var ) will print the content of the any type of variable $var in "human" readable format

    Example:

    print_r( $john ); Output: myObject Object ( [name] => John Smith [bal] => 40000 )

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  • Example Program: (Demo above code)                                                

    ssh -X holland Run: php /home/cs377001/PHP/intro-PHP/object1.php

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• Comment: PHP objects are dynamic
  • Comment:

    Objects in PHP can change its structure: class myObject { public $name; public $bal; } $john = new myObject(); $john->name = "John Smith"; $john->bal = 40000; $john->newField = 123; // You can add another field !!

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  • Example Program: (Demo above code)                                                

    ssh -X holland Run: php /home/cs377001/PHP/intro-PHP/object2.php