🐘 PHP Backend Fundamentals

This repository contains a collection of beginner-to-intermediate PHP scripts designed to demonstrate core server-side programming concepts. Each program focuses on processing form data, performing calculations, and returning results to the client.

This project serves as a backend counterpart to a JavaScript fundamentals collection, translating client-side logic into robust server-side applications.

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📂 Project Structure

This project assumes most scripts are paired with a basic HTML form (either in the same file or a separate .html file) that submits data using the POST or GET method.

PHP_Basics/
│
├── factorial.php             → Calculates the factorial of a user-submitted number
├── odd_even.php              → Checks if a number is odd or even
├── prime_check.php           → Checks whether a number is prime
├── max_of_three.php          → Finds the largest of three submitted numbers
├── armstrong.php             → Checks if a number is an Armstrong number
├── fibonacci.php             → Generates the Fibonacci series up to a given limit
├── swap_values.php           → Swaps two values using a custom PHP function
├── string_reverse.php        → Reverses a string using the built-in strrev() function
├── calculator.php            → Adds or multiplies two numbers from form input
├── random_number.php         → Generates a random number within a specified range
├── form_validation.php       → Validates form fields (checks for empty, valid email, etc.)
│
├── login/
│   ├── login.php             → User login form and authentication logic
│   ├── welcome.php           → A secure "welcome" page shown after successful login
│   └── style.css             → CSS for styling the login page
└── ... (other files)

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⚙️ How to Run

These are server-side scripts and cannot be run by opening the files directly in a browser. You need a local server environment.

1. Install a Local Server Stack:

   • Download and install a package like XAMPP, WAMP, or MAMP. This bundles Apache (web server), PHP, and MySQL (database).

2. Start Your Server:

   • Run your control panel (e.g., XAMPP Control Panel) and start the Apache service.

3. Clone the Repository:

   • Clone this project into the web server's root directory. The name of this directory varies:
     • XAMPP: C:\xampp\htdocs\
     • WAMP: C:\wamp\www\
     • MAMP: /Applications/MAMP/htdocs/

   git clone https://github.com/DEMiHAT/php-basics.git

4. Access in Browser:

   • Open your web browser and navigate to the project's folder using localhost.
   • Example: http://localhost/PHP_Basics/factorial.php or http://localhost/PHP_Basics/login/login.php

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🧩 Concepts Demonstrated

• Form Handling: Capturing data using superglobals like $_POST and $_GET.
• Server-Side Logic: Performing calculations and operations on the server.
• PHP + HTML Integration: Embedding PHP logic within an HTML page to display dynamic results.
• Conditional Logic: Using if, else, elseif, and switch statements.
• Loops: Iterating with for, while, and do-while loops (for Factorial, Fibonacci, Prime).
• Functions:
  • Custom Functions: Defining and using your own functions (like for swapping).
  • Built-in Functions: Using PHP's standard library (strrev(), rand(), isset(), empty()).
• State Management: Using Sessions (session_start(), $_SESSION) for the login system.
• Data Validation: Sanitizing and validating user input (filter_var(), regex).

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🛠️ Technologies Used

Technology	Purpose
PHP	All server-side logic, calculations, and data processing
HTML5	Provides the user interface and forms to submit data
CSS3	Used for styling the login page and other forms
Local Server Stack	(e.g., XAMPP, WAMP) to run and test the PHP scripts

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👨‍💻 Author

Sanjeev Sriram 📧 sanjeevsriram06@gmail.com 🌐 https://github.com/DEMiHAT

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“God will steer the boat, But you must row.” 🪄