PHP Basics

<?php // The opening PHP tag

// A single line comment

# Also a single line comment

/* A multi-line comment
Lorem ipsum dolor, sit amet consectetur adipisicing elit. Neque, earum magnam quis quisquam enim ea animi ipsam. Nostrum, officiis et. */

/* A PHP closing tag is required when content other than PHP is included in the code block, but is optional if not. */

?>

<?php

/*
PHP can be run in a browser using a web server such a Apache.
It can also run in a terminal.
Copy this block of code and paste into a new file 'basics.php'.
Navigate to the directory which contains 'basics.php'.
At the command prompt enter: php basics.php
*/

# The 'echo' keyword tells PHP to output some text
echo "Hello World!\n";

/* PHP stores text in 'strings' enclosed in single or double quotes.
Double quoted strings can hold special characters like '\n' which tells PHP to start a new line. */
echo "I am some text\n";
echo "I am some text on a new line\n";

/* PHP statements are terminated with a semi-colon,
although the PHP closing tag implies a semi-colon.*/
echo "No semi-colon is a no-no!\n";

# Using semi-colons multiple statments can be written on the same line.
echo "PHP"; echo " Apprentice";

# No closing tag required in this case but included in this case.

?>

Hello World!
I am some text
I am some text on a new line
No semi-colon is a no-no!
PHP Apprentice

<?php

/*
The browser output doesn't display as expected.
The new line special character '\n' has no effect in the browser.
Instead we can use '<br>' and rewrite the code as follows:
*/

echo "Hello World!<br>";
echo "I am some text<br>";
echo "I am some text on a new line<br>";
echo "No semi-colon is a no-no!<br>";
echo "PHP"; echo " Apprentice";

?>