Let's begin with a classic programming example — "Hello World". This program serves as the first step for many in programming, demonstrating the basic principles of the language.

Code Syntax

Let's break down the syntax of this program in detail:

1. <?php and ?>: These indicate the start and end of PHP code. All PHP instructions must be placed between these tags. This defines that the text within these tags will be interpreted as PHP code;

2. echo: This is a PHP language construct used to output data. In our case, we use echo to display the string "Hello, World!";

3. "Hello, World!": This is the text we are echoing with echo. In PHP, strings can be specified in either single or double quotes. It's important that the closing quote matches the opening one;

4. The semicolon (;) is used to terminate statements. This is necessary so that the PHP interpreter knows where one command ends and the next begins. Without the semicolon, PHP wouldn't be able to correctly parse the code, leading to syntax errors.