RinniSwift

// 1. empty array initialization
let numbers = [Int]()
let nums: [Int] = []
let newNumbers = Array<Int>()
let newNums: Array<Int> = Array()

// 2. preinitializing a fixed number of default values
let repeatSwift = Array<String>(repeating: "Swift", count: 5) // ["Swift", "Swift", "Swift", "Swift", "Swift"]
// or
let repeatSwift = Array(repeating: "Swift", count: 5)  // ["Swift", "Swift", "Swift", "Swift", "Swift"]

RinniSwift

let array = ["Hello", "people", "of", "the", "world"]

// looping using count property
for ind in 0..<array.count {
  print(ind)
}
// 0, 1, 2, 3, 4

// looping using the endIndex property
for ind in 0..<array.endIndex {

RinniSwift

// 1.
class CircularBuffer<T> {
    
    var bufferMaxSize: Int
    var size = 0
    // 2.
    var elements = Array<T?>(repeating: nil, count: 8)

    // 3.
    init(maxSize: Int) {

RinniSwift

class CircularBuffer<T> {

  // ...

  // 1.
  var front: T? {
    if isEmpty() {
      return nil
    } else {
      // 2.

RinniSwift

class CircularBuffer<T> {

  // ...
  
  func enqueue(item: T) {
    
    // 1.
    if isEmpty() {
      elements[bufferMaxSize-1] = item
    } else {  

RinniSwift

func dequeue() -> T? {

  // ...

  // 1.
  if !isEmpty() {
    // 2.
    let front = elements[bufferMaxSize - size]
    elements[bufferMaxSize - size] = nil
    size -= 1

RinniSwift

class CircularBuffer<T> {
    
  var bufferMaxSize: Int
  var size = 0
  var elements = Array<T?>(repeating: nil, count: 8)

  var front: T? {
    if isEmpty() {
      return nil
    } else {

RinniSwift

// 1. empty set initialization
var numbers = Set<Int>()
var nums: Set<Int> = Set()

// 2. empty set initialization with array literal
var numbersSet: Set<Int> = []

// 3. creating set with predefined elements using array literals
var newNums: Set = [1, 2, 3, 4]

RinniSwift

var numbers = Set<Int>()

numbers.insert(3)   // (true, 3)
numbers.insert(22)  // (true, 22)
numbers.insert(22)  // (false, 22)

RinniSwift

var numbers = Set<Int>(minimumCapacity: 30)
numbers.capacity  // 48