What are generics in Swift and why are they useful?

Generics enable writing flexible, reusable code that works with any type while maintaining type safety.\n\n• **Generic Functions:**\n\nfunc swapValues(_ a: inout T, _ b: inout T) {\n let temp = a\n a = b\n b = temp\n}\n\nvar x = 5, y = 10\nswapValues(&x, &y) // Works with Int\n\nvar str1 = "Hello", str2 = "World"\nswapValues(&str1, &str2) // Works with String\n\n\n• **Generic Types:**\n\nstruct Stack {\n var items: [Element] = []\n \n func push(_ item: Element) {\n items.append(item)\n }\n \n func pop() -> Element? {\n return items.popLast()\n }\n}\n\nvar intStack = Stack()\nvar stringStack = Stack()\n\n\n• **Type Constraints:**\n\nfunc findIndex(of valueToFind: T, in array: [T]) -> Int? {\n for (index, value) in array.enumerated() {\n if value == valueToFind {\n return index\n }\n }\n return nil\n}\n\n\n• **Benefits:**\n• Code reusability\n• Type safety\n• Performance optimization\n• Reduced code duplication