Variable scope in functions in PHP - Mini Project: Build & Apply

Variable scope in functions

📖 Scenario: Imagine you are managing a small shop's sales system. You want to keep track of the total sales amount and update it when a new sale happens. But you need to understand how variables inside and outside functions behave.

🎯 Goal: You will create a variable to hold the total sales, write a function to add a sale amount, and learn how variable scope works in PHP functions.

📋 What You'll Learn

Create a variable called $totalSales and set it to 0

Create a variable called $newSale and set it to 150

Write a function called addSale that takes one parameter $amount

Inside addSale, add $amount to $totalSales using the global keyword

Call the function addSale with $newSale

Print the value of $totalSales after the function call

💡 Why This Matters

🌍 Real World

Understanding variable scope helps you manage data correctly in programs, like tracking sales or inventory in a shop system.

💼 Career

Many programming jobs require you to write functions that update shared data. Knowing variable scope prevents bugs and makes your code reliable.

1

Create initial sales variables

Create a variable called $totalSales and set it to 0. Then create a variable called $newSale and set it to 150.

PHP

$totalSales = 0;
$newSale = 150;
# Your code here

Need a hint?

Use = to assign values to variables. Remember to end each line with a semicolon.

2

Write the addSale function

Write a function called addSale that takes one parameter $amount. Inside the function, use the global keyword to access $totalSales and add $amount to it.

PHP

$totalSales = 0;
$newSale = 150;

function addSale($amount) {
    # Your code here
}

Need a hint?

Use global $totalSales; inside the function to access the variable outside.

3

Call the addSale function

Call the function addSale with the variable $newSale as the argument.

PHP

$totalSales = 0;
$newSale = 150;

function addSale($amount) {
    global $totalSales;
    $totalSales += $amount;
}

# Your code here

Need a hint?

Call the function by writing its name and passing $newSale inside parentheses.

4

Print the total sales

Print the value of $totalSales using echo.

PHP

$totalSales = 0;
$newSale = 150;

function addSale($amount) {
    global $totalSales;
    $totalSales += $amount;
}

addSale($newSale);

# Your code here

Need a hint?

Use echo $totalSales; to show the total sales amount.