Object Oriented Programming
Object Oriented Programming :
An
application can be designed using different programming structures like .
1.
Procedure
oriented programming (pop).
2.
Object
oriented programming (oop).
3.
Aspect
oriented programming .
in
a procedure oriented programming the two entities of an application there
is data and function are treated
separately . so , the complexity to develop an application is more.
And
a global data can be accessed by any one from any where in the program. To
overcome the limitations of procedure oriented programming , oops is introduced
. in oops the two entities of an application there is data and functions are
treated as a single entity, so the complexity to develop an application is
less.
Oops
is mainly based on class and objects as per object oriented analysis and design
so many definitions are given for a class.
In
that the two well known definitions are .
1.
Class
is a concept.
2.
Class
is a blue print.
A
concept contains items and functionalities each item of a concept is used by performing
the particular function.
In
a programming language a class is user defined datatype that contains
attributes are datamembers and methods . which work on data members.
Every
class definition begins with the keyword class followed by a class name.
Class<class-name>
{
Member data;
Methods;
}
Access
specifiers;
The
member datas of a class should be explicitly access specifier.
Access
specifiers a re used to specify from where we can invoke the member data method
etc.
The
fundamental access specifiers used in php are ,
1. private
: private access
specifier members can be accessed only with in the context where it is
declared.
2. Protected
: protected
access specified members can be invoked from within context and also by the
subclass.
3. Public
: public access specified members can be invoked
from any where.
The default access
specifier of php is PUBLIC.
a
pseudo variable , $this is available inside the member function of a class when
it is called from within an object context. $this is a reference to the calling
object inside the class member function.
An
object is a living instance or a real instance of a class .this means that an
object is created from the definition of the class and is loaded in memory[heap
memory].
Each
object has its own memory space that can hold independent data values.
To
create an object of a php class were the keyword “new”.
Obj_ref=
new classname();
An
object can invoke its members by using deferencing operator or arrow
operator(->).
<?php
class empref
{
private $empno,$ename,$sal;
function setData()
{
$this->empno=101;
$this->ename="penna";
$this->sal=12000;
}
function getData()
{
echo
$this->empno."--".$this->ename."--".$this->sal;
}
}
?>
<?php
$emp =new empref();
//echo $emp->empno;
//$emp->getData();
$emp->setData();
$emp->getData();
?>
OutPut:
101--penna—12000
It is nice article for beginners.thank you.
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