hello-algo/en/codes/swift/chapter_stack_and_queue/array_stack.swift

86 lines
1.8 KiB
Swift

/**
* File: array_stack.swift
* Created Time: 2023-01-09
* Author: nuomi1 (nuomi1@qq.com)
*/
/* Stack class based on array */
class ArrayStack {
private var stack: [Int]
init() {
// Initialize the list (dynamic array)
stack = []
}
/* Get the length of the stack */
func size() -> Int {
stack.count
}
/* Determine if the stack is empty */
func isEmpty() -> Bool {
stack.isEmpty
}
/* Push */
func push(num: Int) {
stack.append(num)
}
/* Pop */
@discardableResult
func pop() -> Int {
if isEmpty() {
fatalError("Stack is empty")
}
return stack.removeLast()
}
/* Access stack top element */
func peek() -> Int {
if isEmpty() {
fatalError("Stack is empty")
}
return stack.last!
}
/* Convert the List to Array and return */
func toArray() -> [Int] {
stack
}
}
@main
enum _ArrayStack {
/* Driver Code */
static func main() {
/* Initialize stack */
let stack = ArrayStack()
/* Element push */
stack.push(num: 1)
stack.push(num: 3)
stack.push(num: 2)
stack.push(num: 5)
stack.push(num: 4)
print("Stack stack = \(stack.toArray())")
/* Access stack top element */
let peek = stack.peek()
print("Top element peek = \(peek)")
/* Element pop */
let pop = stack.pop()
print("Popped element pop = \(pop), stack after pop = \(stack.toArray())")
/* Get the length of the stack */
let size = stack.size()
print("Stack length size = \(size)")
/* Determine if it's empty */
let isEmpty = stack.isEmpty()
print("Is the stack empty = \(isEmpty)")
}
}