Access modifiers (public, private, protected) in PHP - Mini Project: Build & Apply

Access Modifiers in PHP Classes

📖 Scenario: You are creating a simple PHP class to represent a bank account. You want to control how the account's balance can be accessed and changed to keep it safe.

🎯 Goal: Build a PHP class called BankAccount with public, private, and protected properties and methods to understand how access modifiers work.

📋 What You'll Learn

Create a class named BankAccount

Add a public property called owner with the owner's name

Add a private property called balance with the initial amount

Add a protected method called formatBalance that returns the balance formatted as a string with a dollar sign

Add a public method called getBalance that uses formatBalance to return the formatted balance

Add a public method called deposit that adds money to the balance

💡 Why This Matters

🌍 Real World

Access modifiers help protect sensitive data in real applications like bank accounts, user profiles, or settings.

💼 Career

Understanding access modifiers is essential for writing secure and maintainable object-oriented code in PHP development jobs.

1

Create the BankAccount class with properties

Create a class called BankAccount with a public property owner set to "Alice" and a private property balance set to 1000.

PHP

# Create the BankAccount class with owner and balance properties
class BankAccount {
    // Your code here
}

Need a hint?

Use public and private keywords before the property names inside the class.

2

Add a protected method to format the balance

Inside the BankAccount class, add a protected method called formatBalance that returns the balance formatted as a string with a dollar sign, like "$1000".

PHP

<?php
class BankAccount {
    public string $owner = "Alice";
    private float $balance = 1000;

    // Add the protected formatBalance method below
    // Your code here
}

Need a hint?

Use protected function formatBalance() and return the balance with a dollar sign.

3

Add public methods to get balance and deposit money

Add two public methods inside BankAccount: getBalance that returns the result of formatBalance(), and deposit that takes a float $amount and adds it to balance.

PHP

balance;
    }

    // Add public getBalance and deposit methods below
    // Your code here
}

Need a hint?

Use public function getBalance() to call formatBalance() and public function deposit(float $amount) to add to balance.

4

Create an object, deposit money, and print the balance

Create a BankAccount object called account. Call deposit(500) on it. Then print the owner's name and the balance using getBalance().

PHP

balance;
    }

    public function getBalance(): string {
        return $this->formatBalance();
    }

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

// Create account, deposit 500, and print owner and balance
// Your code here

Need a hint?

Create the object with new BankAccount(), call deposit(500), then print the owner's name and balance.