Strictly speaking, there's no difference, since you cannot do either :]
Function overriding could have been done with a PHP extension like APD, but it's deprecated and afaik last version was unusable.
Function overloading in PHP cannot be done due to dynamic typing, ie, in PHP you don't "define" variables to be a particular type. Example:
$a=1;
$a='1';
$a=true;
$a=doSomething[];
Each variable is of a different type, yet you can know the type before execution [see the 4th one]. As a comparison, other languages use:
int a=1;
String s="1";
bool a=true;
something a=doSomething[];
In the last example, you must forcefully set the variable's type [as an example, I used data type "something"].
Another "issue" why function overloading is not possible in PHP: PHP has a function called func_get_args[], which returns an array of current arguments, now consider the following code:
function hello[$a]{
print_r[func_get_args[]];
}
function hello[$a,$a]{
print_r[func_get_args[]];
}
hello['a'];
hello['a','b'];
Considering both functions accept any amount of arguments, which one should the compiler choose?
Finally, I'd like to point out why the above replies are partially wrong; function overloading/overriding is NOT equal to method overloading/overriding.
Where a method is like a function but specific to a class, in which case, PHP does allow overriding in classes, but again no overloading, due to language semantics.
To conclude, languages like Javascript allow overriding [but again, no overloading], however they may also show the difference between overriding a user function and a method:
/// Function Overriding ///
function a[]{
alert['a'];
}
a=function[]{
alert['b'];
}
a[]; // shows popup with 'b'
/// Method Overriding ///
var a={
"a":function[]{
alert['a'];
}
}
a.a=function[]{
alert['b'];
}
a.a[]; // shows popup with 'b'
Method Overloading and Method overriding method is a very useful feature of any object-oriented programming language. In this section, we will discuss how to implement function overloading and function overriding in PHP. In object-oriented programming concept if functions of the class have the same name but different in parameters are termed as overloading and if the functions of the class are the same as well as parameter then it is termed as overriding.
Function Overloading
It contains the same function name and that function performs different tasks according to the number of arguments. For example, find the area of certain shapes where the radius is given then it should return the area of a circle if height and width are given then it should give the area of rectangle and others. Like other OOP languages, function overloading cannot be done by the native approach. In PHP overloading is done with the help of magic function. This function takes function arguments and name.
How to use overloading in PHP?
class MainClass {
public function ShowTitle[$parameter1] {
echo “Best Interview Question”;
}
public function ShowTitle[$parameter1, $parameter2] {
echo “BestInterviewQuestion.com”;
}
}
$object = new
MainClass;
$object->ShowTitle[‘Hello’];
Output:
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Fatal error: Cannot redeclare MainClass::ShowTitle[]
class
Resolve{
const Pi = 3.142 ;
function __call[$fname, $arg]{
if[$name == ‘area’]
switch[count[$arg]]{
case 0 : return 0 ;
case 1 : return self::Pi * $arg[0] ;
case 2 : return $arg[0] * $ arg[1];
}
}
}
$circle = new Resolve[];
echo “Area of circle:”.$circle->area[5].””;
$rect = new Resolve[];
echo “Area of rectangle:”.$rect->area[5,10];
Output
Area of circle:15.71Area of rectangle:50
Function Overriding
It is the same as other OOPs programming languages. In this function, both parent and child classes should have the same function name and number of arguments. It is used to replace the parent method in child class. The purpose of function overriding is to change the behavior of the parent class method. The two functions with the same name and the same parameter are called function overriding.
class ParentClass {
function helloWorld[] {
echo “Parent”;
}
}
class ChildClass extends ParentClass {
function helloWorld[] {
echo “\nChild”;
}
}
$p = new ParentClass;
$c= new ChildClass;
$p->helloWorld[];
$c->helloWorld[];
Output:
Parent
Child
In PHP, there are various arrays functions that allow us to access and manipulate arrays. If you want to read these PHP array functions then you can visit here.
Conclusion
Function Overloading is defining methods that have similar signatures, yet have different parameters. Function Overriding is only pertinent to derived classes, where the parent class has defined a method and the derived class wishes to override that method. If you want to read more about OOPS Concepts then you can visit here.
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