"Hello World" Explained

Here’s the code from the previous lesson:

Let’s take a look at this in detail.

We’ll start from the very first line and go step by step!

PHP Opening Tag

A PHP script can be written anywhere in the document, and it signifies the start of the PHP code.

echo

PHP uses a built-in function called echo in order to display one or more strings.

Tip: The echo function is faster than the print() function.

Note: You may use parentheses with the echo function as echo ("string"); but it isn’t compulsory because echo isn’t really a function.

PHP Closing Tag

The PHP closing tag marks the end of the PHP code. It is written as:

Note: All code in PHP is written between the starting (<?php) and ending (?>) symbol. However, the closing tag of a PHP code block at the end of a file is optional. The code would still execute properly even if the closing tag is missing.

Semicolons

Statements in PHP must be terminated with a semicolon.

• Just as sentences in English must be terminated with a period.
• Just as sentences in English can span several lines, so can the statements in PHP.

You can use as many spaces and newlines between the start and end symbol of a PHP program as you wish. It helps beautify your code just as spaces are used to align the text printed on the pages of a book.

Comments in PHP

Comments in PHP are used to explain code and make it easier to read. PHP ignores comments when executing the program.

PHP supports single-line comments and multiple-line comments.

A single-line comment can be written using // or #:

<?php
// This is a single-line comment
# This is also a single-line comment
echo "Hello, World!\n";
?>

A multiple-line comment is written using /* and */:

<?php
/* This is a
multiple-line comment */
echo "Hello, World!\n";
?>

Comments are useful when you want to describe what a piece of code does or temporarily disable a line while testing.

Now that we have learned the basics of PHP syntax, let’s take a quick quiz in the next lesson.