Achieve Method Overriding in PHP

Question

I have implemented method overriding in OOPS, but I'm not sure how method overriding is achieved in PHP. When you create a function with the same name, it will give you an error about the redeclaration of the function.

Answer 1

Method overriding in PHP is actually quite simple. You just specify the base class and then create a method (function) with the same name within the derived class.

class BaseClass {
  public function first_method() {
    echo("Hello! I am the base!\n");
  }
  public function do_something() {
    echo("Hi, there! I am the base!\n");
  }
}

class AnotherClass extends BaseClass {
  public function do_something() {
    echo("Hi, there! I am a derivative!\n");
  }
}

$base_class = new BaseClass();
$another_class = new AnotherClass();
$base_class->do_something();
$another_class->do_something();
$another_class->first_method();

Edit to Cover the Possible Question on Method Overloading :-)

In case you meant to ask about method overloading, then you should know it can't be done in PHP. There is another feature which can eventually give you the same result: default arguments. Here is a potential use case applicable to both, methods and functions:

function first_function($a, $b=NULL) {
  echo($a);
  if($b!==NULL) {
    echo($b);
  }
}

This is essentially the same as having two functions named first_function (in C++, for example), where each function has a different number of parameters, like this:

void first_function(int a) {
  cout << a << endl;
}

void first_function(int a, int b) {
  cout << a << endl;
  cout << b << endl;
}

It makes more sense to avoid conventional method overloading because PHP is a loosely typed language. Ending with two functions with same number of arguments would lead to a dead end because PHP interpreter wouldn't be able to determine which of these two functions you wanted to call, since there is no type sensitivity in PHP.