Source Code: (back to article)

<?php

// Example 1
class Animal
{
  protected $name;

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

protected function getName()
  {
    return $this->name;
  }
}

class Dog extends Animal
{
  public function bark()
  {
    $name = $this->getName();
    echo "$name barks!" . PHP_EOL;
  }
}

$dog = new Dog("Rufus");
$dog->bark(); // Output: Rufus barks!

// Example 2
class BankAccount
{
  protected $balance = 0;

public function deposit($amount)
  {
    $this->balance += $amount;
  }

protected function canWithdraw($amount)
  {
    return $amount <= $this->balance;
  }
}

class SavingsAccount extends BankAccount
{
  public function withdraw($amount)
  {
    if ($this->canWithdraw($amount)) {
      $this->balance -= $amount;
      echo "Withdrawal successful!" . PHP_EOL;
    } else {
      echo "Insufficient funds!" . PHP_EOL;
    }
  }
}

$savingsAccount = new SavingsAccount();
$savingsAccount->deposit(100);
$savingsAccount->withdraw(50); // Output: Withdrawal successful!
$savingsAccount->withdraw(100); // Output: Insufficient funds!

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