What is PHP? History and versions
Installing PHP, Apache, MySQL (XAMPP/WAMP/LAMP)
Basic syntax and PHP tags
Embedding PHP in HTML
Variables and constants
Data types (Integer, Float, String, Boolean, Array, Object, NULL)
Type casting
Arithmetic, Assignment, Comparison, Logical, Increment/Decrement, String operators
Conditional statements (if, if-else, if-elseif-else, switch)
Loops (while, do-while, for, foreach)
Break, continue, exit/die
Defining and calling functions
Function arguments (default, dynamic, return values)
Variable scope (global, local, static)
Built-in functions (string, array, date/time, math)
Anonymous functions and closures
Indexed, Associative, Multidimensional arrays
Array functions (array_push, array_pop, array_merge, etc.)
Array iteration (foreach, array_map, array_filter)
Form submission (GET and POST)
$_GET, $_POST, $_REQUEST, $_SERVER
Input validation and sanitization
String manipulation functions (strlen, strpos, substr, etc.)
Regular expressions (preg_match, preg_replace)
Reading and writing files
fopen, fread, fwrite, fclose
File handling functions (file_exists, filesize, etc.)
