Swift: Missing Argument Error - swift

Question

Im having an issue here when trying to follow the first stanford lecture. I am assuming it is because I am using swift 2.... which was just recently released. (And the class is not) Below I show where I am getting errors. In the class the "enter" button on the calculator has the code #IBAction func enter() { but in mine it is #IBAction func enter(sender: UIButton) {
Is this something I did wrong when bringing the button into my code? Any ways to fix? Let me know if I can clarify anything.
import UIKit
class ViewController: UIViewController
{
#IBOutlet var display: UILabel!
var userIsInTheMiddleOfTypingANumber: Bool = false
#IBAction func appendDigit(sender: UIButton) {
let digit = sender.currentTitle!
if userIsInTheMiddleOfTypingANumber {
display.text = display.text! + digit
} else {
display.text = digit
userIsInTheMiddleOfTypingANumber = true
}
}
#IBAction func operate(sender: UIButton) {
let operation = sender.currentTitle!
if userIsInTheMiddleOfTypingANumber {
enter() // Here is my error: *Missing Argument for parameter on the line of code that says enter()
}
switch operation {
case "x":
if operandStack.count >= 2 {
displayValue = operandStack.removeLast() * operandStack.removeLast()
enter() // Here is my error: Again...
}
default: break
}
}
var operandStack = Array<Double>()
#IBAction func enter(sender: UIButton) {
userIsInTheMiddleOfTypingANumber = false
operandStack.append(displayValue)
print("operandStack = \(operandStack)")
}
var displayValue: Double {
get {
return NSNumberFormatter().numberFromString(display.text!)!.doubleValue
}
set {
display.text = "\(newValue)"
userIsInTheMiddleOfTypingANumber = false
}
}
}

Answer 1

enter requires an input parameter but you didn't supply it with any. Replace it with enter(sender)
#IBAction func operate(sender: UIButton) {
let operation = sender.currentTitle!
if userIsInTheMiddleOfTypingANumber {
enter(sender)
}
switch operation {
case "x":
if operandStack.count >= 2 {
displayValue = operandStack.removeLast() * operandStack.removeLast()
enter(sender)
}
default: break
}
}