PHP Interview Preparation

PHP Interview Questions

• Pass by Value vs Reference: PHP passes by value by default — function changes don't affect the original. Use & for pass by reference: function increment(&$num) { $num++; }. Objects are always passed by reference handle
• Abstract vs Interface: Abstract class can have implemented methods and properties — subclass extends ONE abstract class. Interface defines a contract (method signatures only) — class implements MULTIPLE interfaces. PHP 8 interfaces can have constants
• PHP Autoloading: spl_autoload_register or Composer's PSR-4 autoloading — classes loaded automatically when first used. No manual require/include. composer.json defines namespace-to-directory mapping
• Traits: Reusable method blocks — use SoftDeletes; adds soft delete functionality. Solves single inheritance limitation. Conflict resolution with insteadof and as operators
• PHP Type System: Strict types: declare(strict_types=1) enforces type declarations. Union types (PHP 8), intersection types (PHP 8.1), nullable (?string), void, never, mixed return types
• Design Patterns in PHP: Singleton (database connection), Factory (object creation), Repository (data access abstraction), Observer (event system), Strategy (payment methods), Decorator (middleware)

Quick Quiz — PHP Career