Stack

public struct Stack<T>

A Stack is a Last-In-First-Out (LIFO) collection, the last element added to the stack will be the first one to be removed.

The push and pop operations run in amortized constant time.

Conforms to Sequence, ExpressibleByArrayLiteral, CustomStringConvertible.

Creating a Stack

  • Constructs an empty stack.

    Declaration

    Swift

    public init()

  • Constructs a stack from a sequence, such as an array. The elements will be pushed from first to last.

    Declaration

    Swift

    public init<S: Sequence>(_ elements: S) where S.Iterator.Element == T

Querying a Stack

  • Number of elements stored in the stack.

    Declaration

    Swift

    public var count : Int

  • Returns true if and only if count == 0.

    Declaration

    Swift

    public var isEmpty: Bool
  • top

    The top element of the stack, or nil if the stack is empty.

    Declaration

    Swift

    public var top: T?

Adding and Removing Elements

  • Inserts an element into the top of the stack.

    Declaration

    Swift

    public mutating func push(_ element: T)

  • Retrieves and removes the top element of the stack.

    Declaration

    Swift

    public mutating func pop() -> T

    Return Value

    The top element.

  • Removes all the elements from the stack, and by default clears the underlying storage buffer.

    Declaration

    Swift

    public mutating func removeAll(keepingCapacity keep: Bool = false)

Sequence Protocol Conformance

  • Provides for-in loop functionality. Generates elements in LIFO order.

    Declaration

    Swift

    public func makeIterator() -> AnyIterator<T>

    Return Value

    A generator over the elements.

ExpressibleByArrayLiteral Protocol Conformance

  • Constructs a stack using an array literal. The elements will be pushed from first to last. let stack: Stack<Int> = [1,2,3]

    Declaration

    Swift

    public init(arrayLiteral elements: T...)

CustomStringConvertible Protocol Conformance

  • A string containing a suitable textual representation of the stack.

    Declaration

    Swift

    public var description: String