You're building a compiler that needs to perform multiple operations on an abstract syntax tree: type checking, code generation, optimization. Adding each operation as a method to every node class…
You're building a data processing system with multiple report generators. Each report follows the same steps: fetch data, process data, format output, send notification. The steps are the same, but…
You're building a payment processing system that needs to support multiple payment methods: credit card, PayPal, bank transfer. Using if/else statements for each method creates tight coupling and makes adding…
You're building a vending machine. It behaves differently when it has no money, has money, is dispensing, or is out of stock. Using if/else statements for every state creates complex,…
You're building a text editor with undo functionality. Users need to revert to previous document states, but exposing internal state would break encapsulation. The Memento pattern lets you save and…
You're building a dialog box with multiple UI components: buttons, text fields, checkboxes. When one component changes, others need to update. Without careful design, every component would need references to…