teaching_web_development

Introduction to PHP

PHP (Hypertext Preprocessor) is a popular server-side scripting language designed for web development but also used as a general-purpose programming language.

It is especially suited for creating dynamic web pages and applications.

Key Features of PHP

Server-Side Scripting: PHP code is executed on the server, generating HTML that is sent to the client’s browser.
Embedded in HTML: PHP can be embedded directly within HTML code, making it easy to create dynamic web content.
Database Integration: PHP has built-in support for various databases, including MySQL, PostgreSQL, and SQLite, allowing for dynamic data-driven applications.
Cross-Platform: PHP runs on various platforms, including Windows, Linux, and macOS, making it versatile for different server environments.
Open Source: PHP is free to use and has a large community that contributes to its development and provides support.

Video Tutorial

Video Tutorial on PHP by Dr. Chuck Severance

Getting Started with PHP

Installation Instructions
Run on server
Start MAMP on your machine.

_ Click on “Start” to start the Apache server.

Navigate to http://localhost:8888 or http://localhost:8888/MAMP/?language=English in your web browser to verify that the server is running.

Configuring PHP

Edit the file php.ini to configure PHP settings.

On my Mac OS X, the file is located at:

/Applications/MAMP/bin/php/php8.3.28/conf/php.ini

The contents of php.ini look like this:

; PHP's initialization file, generally called php.ini, is responsible for
; configuring many of the aspects of PHP's behavior.
;
; This file is divided into sections, each section having directives that
; configure various aspects of PHP's behavior. Each directive is explained
; via comments in this file.
;
; For more information about setting up PHP, please refer to the
; documentation at https://www.php.net/manual/en/configuration.file.php

Start writing PHP code in your web server’s document root directory (e.g., htdocs for MAMP).
On my Mac OS X, the document root directory is located at:
```
/Applications/MAMP/htdocs
```
In this directory, create a new folder named my_php_site.
In this folder, create a file with a .php extension (e.g., index.php) to start writing your PHP code.
Open your favorite code editor (e.g., VS Code, vi, Sublime Text, or any text editor) to write PHP code.
Write the PHP code in the .php file you created.

<?php
// Your PHP code goes here
echo "Hello World!";
?>

Navigate to http://localhost:8888/my_php_site/index.php in your web browser to see the output of your PHP code.

PHP Script

A PHP script is typically enclosed within <?php and ?> tags.
A PHP file usually has a .php extension.
A PHP script can generate HTML content dynamically.

Syntax Basics

PHP Syntax
PHP Variables
PHP is loosely typed, meaning you do not need to declare variable types explicitly.
Static typing can be found in C++ or Java, where you must declare the type of a variable before using it.
Dynamic typing means that the type is determined at runtime based on the value assigned to the variable.
For example:

<?php
$age = 25; // $age is an integer
$name = "Alice"; // $name is a string
$price = 19.99; // $price is a float
?>

Examples

PHP Examples
Example code snippets:

<?php
// Example 1: Variables and Output
$name = "John";
echo "Hello, " . $name . "!"; // Outputs: Hello, John!
?>

<?php
// Example 2: Conditional Statements
$age = 20;
if ($age >= 18) {
    echo "You are an adult.";
} else {
    echo "You are a minor.";
}
?>

<?php
// Example 3: Looping
for ($i = 1; $i <= 5; $i++) {
    echo "Number: " . $i . "<br>";
}
?>

<?php
// Example 4: Functions
function greet($name) {
    return "Hello, " . $name . "!";
} 

echo greet("Alice"); // Outputs: Hello, Alice!
?>

<?php
// Example 5: Arrays
$fruits = array("Apple", "Banana", "Cherry");
foreach ($fruits as $fruit) {
    echo $fruit . "<br>";
}
?>

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