CODEWITHSUNDEEP
phpoopmethodsabstract-class
samayo
samayo

Reputation: 16495

Abstract Classes in PHP throwing error

I have be below test script, and I am not sure as to why is is giving me errors. But at the same time working as expected (outputting a text 'woof'); 

abstract class Animal { 

abstract function bark(); 
  function MakeDog(){
        return $this->bark();
  } 

} 

class Dog extends Animal { 
  function bark(){
    echo 'Woof';
  }
} 


$dog = new Dog(); 
echo $dog->MakeDog()->bark(); // this outputs 'woof' but with error. 


Fatal error: Call to a member function bark() on a non-object in [...] 26

Line 26 is //echo $dog->MakeDog()->bark(); I am not sure to what the error is related to.

Upvotes: 0

Views: 175

Answers (3)

Renato Leite
Renato Leite

Reputation: 791

You can't call bark() after the method MakeDog() and you can't use echo for return a message, for this use "return", the correct code:

<?php

abstract class Animal { 

    abstract function bark(); 

    public function MakeDog(){
        return $this->bark();
    } 

} 

class Dog extends Animal { 

    function bark(){
        return 'Woof';
    }

} 

$dog = new Dog(); 

echo $dog->MakeDog();

?>

Upvotes: 1

Brian
Brian

Reputation: 1065

Shouldn't it just be:

$dog = new Dog();
echo $dog->MakeDog();

Your function MakeDog already executes the method bark().

Upvotes: 1

user2672373
user2672373

Reputation:

Perhaps you don't need to echo even. This should work

$dog = new Dog();
$dog->MakeDog()->bark();

Also, get rid of return just invoke bark() in the MakeDog function

function MakeDog() {
    $this->bark();    
}

Upvotes: 1

Related Questions