Explain the Strategy pattern with examples.

Strategy pattern defines a family of algorithms, encapsulating each one and making them interchangeable. Context holds reference to strategy interface; concrete strategies implement algorithm variations. Examples: payment processing (CreditCard, PayPal, Crypto strategies), sorting algorithms, validation rules, shipping calculators. Benefits: eliminates conditional statements, follows Open/Closed principle, supports runtime algorithm switching. Often combined with Factory to create strategies. Similar to State pattern but for algorithms, not state transitions.