ZEND PHP 5 Certification STUDY GUIDE

Object Oriented Programming in PHP ” 115
In this case, both $myInstance and $copyInstance will point to the same object, even
though we didn’t specify that we wanted this to happen by means of any special
syntax. This is the standard behaviour of objects in most languages, but wasn’t the
case in PHP 4, where objects were handled like any other normal variables and were,
therefore, passed by value.
Class Inheritance
One of the key fundamental concepts of OOP is inheritance. This allows a class to extend
another class, essentially adding new methods and properties, as well as overriding
existing ones as needed. For example:
class a {
function test()
{
echo "a::test called";
}
function func()
{
echo "a::func called";
}
}
class b extends a {
function test()
{
echo "b::test called";
}
}
class c extends b {
function test()
{
parent::test();
}
}
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class d extends c {
function test()
{
b::test();
}