Try It Yourself - SyntaxStudy Editor

HTML / CSS / JS

// inout parameters
func swap<T>(_ a: inout T, _ b: inout T) {
    let temp = a
    a = b
    b = temp
}
var x = 10, y = 20
swap(&x, &y)
print(x, y)  // 20 10

// Generic function with constraint
func findFirst<T: Equatable>(_ item: T, in array: [T]) -> Int? {
    for (index, element) in array.enumerated() {
        if element == item { return index }
    }
    return nil
}
findFirst("banana", in: ["apple", "banana", "cherry"])  // Optional(1)

// Multiple constraints
func showMax<T: Comparable & CustomStringConvertible>(_ a: T, _ b: T) -> String {
    let max = a > b ? a : b
    return "Max: \(max.description)"
}

// Where clause on generic
func allUnique<T: Hashable>(_ array: [T]) -> Bool {
    Set(array).count == array.count
}
allUnique([1, 2, 3, 4])   // true
allUnique([1, 2, 2, 4])   // false

// Generic type with associated type protocol
protocol Stack {
    associatedtype Element
    mutating func push(_ item: Element)
    mutating func pop() -> Element?
    var top: Element? { get }
}