Please refer this Code input

This code doesn't give the expected output

class User{
        protected $name;
        protected $age;

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

    class Customer extends User{
        private $balance;

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

        public function pay($amount){
            return $this->name . ' paid $' . $amount;
        }
    }

    $customer1 = new Customer('Adithya', 23, 50);
    echo $customer1->pay(100);

It only gives this
Can someone please explain the reason?

CodePudding user response：

Add the following line to the Customer class constructor so that the parent class constructor is called with the right parameters

parent::__construct($name, $age);

So the code is as follows

(I have added a line in the pay method to make it more meaningful)

<?php
class User{
        protected $name;
        protected $age;

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

    class Customer extends User{
        private $balance;

        public function __construct($name, $age, $balance){
            parent::__construct($name, $age);
            $this->balance = $balance;
        }

        public function pay($amount){
            $this->balance = $this->balance - $amount;
            return $this->name . ' paid ' . $amount;
        }

        public function getbalance(){
            return $this->name . ' now has ' . $this->balance ;
        }

    }

    $customer1 = new Customer('Adithya', 23, 50);
    echo $customer1->pay(100);

    echo "<br>";

    echo $customer1->getbalance();
    ?>

The display will be :

Adithya paid 100
Adithya now has -50

(initially Adithya is having 50 as balance, but he has paid 100, so the new balance is -50)

CodePudding user response：

    class Customer extends User{
    private $balance;

    public function __construct($name, $age, $balance){
        $this->balance = $balance;
        parent::__construct($name,$age,$balance);
    }

    public function pay($amount){
        return $this->name . ' paid $' . $amount;
    }
}