Throwing exceptions in PHP - Mini Project: Build & Apply

Throwing exceptions

📖 Scenario: Imagine you are creating a simple bank account system. You want to make sure that if someone tries to withdraw more money than they have, the program will stop and show an error message.

🎯 Goal: You will build a PHP program that throws an exception when a withdrawal amount is greater than the account balance.

📋 What You'll Learn

Create a variable to hold the account balance

Create a variable for the withdrawal amount

Use an if statement to check if withdrawal is greater than balance

Throw an exception with a clear message if withdrawal is too large

Print a success message if withdrawal is allowed

💡 Why This Matters

🌍 Real World

Throwing exceptions is useful in real programs to stop execution when something goes wrong, like invalid input or errors.

💼 Career

Understanding exceptions is important for writing reliable and safe code in many programming jobs.

1

Set up account balance and withdrawal amount

Create a variable called $balance and set it to 1000. Create another variable called $withdrawal and set it to 1200.

PHP

<?php

// Create $balance and $withdrawal variables

Need a hint?

Use simple assignment to create the variables with the exact names and values.

2

Prepare to check withdrawal amount

Create a variable called $canWithdraw and set it to true. This will help us decide if withdrawal is allowed.

PHP

<?php

$balance = 1000;
$withdrawal = 1200;

// Create $canWithdraw variable and set it to true

Need a hint?

This variable will be used to track if withdrawal is possible.

3

Throw exception if withdrawal is too large

Use an if statement to check if $withdrawal is greater than $balance. Inside the if, throw a new Exception with the message 'Withdrawal amount exceeds balance.'.

PHP

<?php

$balance = 1000;
$withdrawal = 1200;
$canWithdraw = true;

// Add if statement to throw Exception if withdrawal is too large

Need a hint?

Use throw new Exception('message'); inside the if block.

4

Print success message if no exception

Add a print statement that outputs 'Withdrawal successful.' after the if block.

PHP

 $balance) {
    throw new Exception('Withdrawal amount exceeds balance.');
}

// Print success message

Need a hint?

The program will stop and show an error message because the withdrawal is too large.