Class Constructor in PHP

In this tutorial, you shall learn how to about constructors in a class in PHP, and how to define a class constructor, with the help of example programs.

PHP – Class Constructor

A constructor in a class is used to initialise the properties of the class objects.

To define a constructor for a class in PHP, define __constructor() method in the class, just like any other function in a class, as shown in the following syntax.

class ClassName() {
    function __construct(parameters) {
        //constructor body
    }
}

• function is keyword
• __construct is the function name, and is fixed for a constructor in class
• parameters: comma separated parameters that this constructor can accept as arguments.

Example

In our previous tutorials in PHP classes and objects series, we have given an example class Person. We shall continue with this class Person to demonstrate how to define a constructor for a class.

Now, let us define a constructor for the class Person. And create an object with arguments passed for the constructor.

PHP Program

<?php
  class Person {
    protected string $fullname;
    protected int $age;

    public function __construct(string $fullname = null, int $age = null) {
      $this->fullname = $fullname;
      $this->age = $age;
    }

    public function printDetails() {
      echo "Name : " . $this->fullname . "<br>Age : " . $this->age;
    }
  }
  
  //create object of type Person with arguments passed for constructor
  $person1 = new Person("Mike Turner", 24);

  //call method on the object
  $person1->printDetails();
?>

Output

Conclusion

In this PHP Tutorial, we learned how to define a constructor for a class, with examples.