Happy Coders

A constructor in PHP is a special method called automatically when an object is created. It is defined using __construct() inside a class. Constructors are used to initialize object properties. They can accept parameters and set default values. PHP also supports type declarations in constructors for better data control.

1. Basic Constructor Example

class User {
    public $name;

    // Constructor method
    public function __construct($userName) {
        $this->name = $userName;
    }

    public function greet() {
        return "Hello, " . $this->name;
    }
}

$user = new User("John");
echo $user->greet(); // Output: Hello, John

File: constructor_basic.php

2. Constructor with Multiple Parameters

class Product {
    public $name;
    public $price;

    public function __construct($name, $price) {
        $this->name = $name;
        $this->price = $price;
    }

    public function getDetails() {
        return "Product: {$this->name}, Price: ₹{$this->price}";
    }
}

$p = new Product("Laptop", 55000);
echo $p->getDetails();

File: product_constructor.php

3. Default Values in Constructor

class Student {
    public $name;
    public $grade;

    public function __construct($name = "Unknown", $grade = "Not Assigned") {
        $this->name = $name;
        $this->grade = $grade;
    }

    public function display() {
        return "{$this->name} is in grade {$this->grade}";
    }
}

$s = new Student();
echo $s->display(); // Output: Unknown is in grade Not Assigned

File: default_constructor.php

4. Constructor with Type Declarations (PHP 7+)

class Employee {
    public string $name;
    public int $salary;

    public function __construct(string $name, int $salary) {
        $this->name = $name;
        $this->salary = $salary;
    }

    public function getInfo() {
        return "{$this->name} earns ₹{$this->salary}";
    }
}

$emp = new Employee("Ravi", 30000);
echo $emp->getInfo();

File: typed_constructor.php

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