What is the correct option to instantiate a PHP class?

Question

What is the correct option to instantiate a PHP class?

Whereas the class is under discussion if call Atleta:

1)

$atleta=Atleta;

2)

$atleta= new Atleta();

3)

$atleta= Atleta();

Which of the 3 options is the right way to instantiate a PHP class?

Answer 1

In the context of the question would be the second option:

$atleta = new Atleta();

But remember that in PHP, it is not necessary to use parentesis () when the class has no constructor or does not need arguments.

Then that would also be valid:

$atleta = new Atleta;

Explanation of each option

I don’t know if I’m wrong, but the question sounds a lot like an evaluative question. So, assuming that, I don’t think it’s cool to just "give the right answer," but explain what each thing does.

$atleta = Atleta;

Generally, this syntax is used in PHP to get the value of a constant.

For example:

const Atleta = 'Atleta';

// ou 

define('Atleta', 'Atleta');

$atleta = Atleta;

Observing: When trying to assign the value of an undefined constant, you will receive an error message of type E_NOTICE and the value assigned will be a string as the name of the nonexistent constant.

$atleta= Atleta();

This syntax is used for the direct function call. Functions in PHP are called with the use of parentesis, can be passed arguments or not.

Example:

 function Atleta() {
       return 'Atleta';
}

$atleta = Atleta();

Answer 2

Is to use option 2 that way:

$atleta= new Atleta();

More information can be found here php.net

Answer 3

According to the official website of PHP, the instruction should be used new to instantiate a class.

If you make instance of an empty generic object the best way is to use the method below:

$obj = new obj(); 

Being the most correct and fast way.

Only going further, in php7 there are other ways to instantiate an empty object:

$obj1 = new \stdClass; //instancia o objeto stdClass
$obj2 = new class{}; //instancia uma classe anônima.

In short, the most used by the community: Libraries, frameworks and etc is with the square brackets.