php language basics
Beginner Milestone: Scripts, Values, And Expressions
PHP example
<?php
const FREE_SHIPPING_THRESHOLD_CENTS = 5_000;
$productName = 'PHP Workbook';
$priceCents = 2_499;
$quantity = 2;
$subtotalCents = $priceCents * $quantity;
$hasFreeShipping = $subtotalCents >= FREE_SHIPPING_THRESHOLD_CENTS;
$shippingLabel = $hasFreeShipping ? 'free' : 'standard';
echo "Item: $productName\n";
echo "Subtotal: $subtotalCents cents\n";
echo "Shipping: $shippingLabel\n";
// Prints:
// Item: PHP Workbook
// Subtotal: 4998 cents
// Shipping: standard
Read the script from top to bottom. The named values make the calculation visible. The subtotal is an integer number of cents, and the comparison produces a boolean used by the short choice at the end.
Change one value at a time and predict the result before rerunning the file. If you can explain why the output changes, you are ready to use the same expressions inside if statements and loops.
Practice
Trace A Cart Total
A notebook costs 750 cents and the quantity is 3. Write a script that calculates and prints the subtotal. Predict the output before running it.
Show solution
PHP example
<?php
$priceCents = 750;
$quantity = 3;
$subtotalCents = $priceCents * $quantity;
echo "$subtotalCents cents\n";
// Prints:
// 2250 cents
Change The Free-Shipping Threshold
Show solution
PHP example
<?php
const FREE_SHIPPING_THRESHOLD_CENTS = 4_500;
$subtotalCents = 4_998;
$shippingLabel = $subtotalCents >= FREE_SHIPPING_THRESHOLD_CENTS ? 'free' : 'standard';
echo "Shipping: $shippingLabel\n";
// Prints:
// Shipping: free
Build An Item Summary
Create variables for a product name, price in cents, and quantity. Print the product name, quantity, and calculated subtotal on separate lines.
Show solution
PHP example
<?php
$productName = 'Pen';
$priceCents = 150;
$quantity = 4;
$subtotalCents = $priceCents * $quantity;
echo "Item: $productName\n";
echo "Quantity: $quantity\n";
echo "Subtotal: $subtotalCents cents\n";
// Prints:
// Item: Pen
// Quantity: 4
// Subtotal: 600 cents