#!/usr/bin/env swift;
/******************************************************************************
 * This program demonstrates the Stack ADT
 * 
 * Copyright © 2021 Richard Lesh.  All rights reserved.
 *****************************************************************************/

import Foundation
import Utils

class IntegerStack {
// Internal representation for the stack is a list
	private var stack:[Int] = []

	public init() {
		stack = []
	}

	public func pop() throws -> Int {
		if stack.count == 0 {
			throw RuntimeError("Can't pop on empty stack!")
		}
		return stack.removeLast()
	}

	public func push(_ value:Int) -> Void {
		stack.append(value)
	}

	public func peek() throws -> Int {
		if stack.count == 0 {
			throw RuntimeError("Can't peek on empty stack!")
		}
		return stack[stack.count - 1]
	}
}

func main() -> Void {
	var stack:IntegerStack = IntegerStack()
	for x:Int in 1...10 {
		stack.push(x)
	}
	do {
		print(String(try stack.peek()))
		for _:Int in 1...11 {
			print(String(try stack.pop()))
		}
	} catch let ex as RuntimeError {
		print(ex.localizedDescription)
	} catch {
		print("Unknown Exception!")
	}
	exit(EXIT_SUCCESS)
}
main()