Making a calculator in Swift - ios

Question

My problem is that I can click and input multiple numbers for my first value but then after I used a math operator (ex. +,-,*,/) it only allows me to input a single value unlike the first time running it.
import UIKit
class ViewController: UIViewController {
#IBOutlet weak var Label: UILabel!
var secondNumber: Double = 0;
var firstNumber: Double = 0;
var performingMath = false
var operatorUsed = 0;
#IBAction func cleartext(_ sender: UIButton) {
Label.text = ""
performingMath = false
}
#IBAction func Numbers(_ sender: UIButton) {
if performingMath {
Label.text = String(sender.tag - 1)
secondNumber = Double(Label.text!)!
performingMath = true
} else {
Label.text = Label.text! + String(sender.tag - 1)
secondNumber = Double(Label.text!)!
}
}
#IBAction func Operators(_ sender: UIButton) {
if Label.text != " " && sender.tag != 11 {
firstNumber = Double(Label.text!)!
if sender.tag == 12 {
Label.text = "+"
} else if sender.tag == 13 {
Label.text = "-"
} else if sender.tag == 14 {
Label.text = "*"
} else if sender.tag == 15 {
Label.text = "/"
}
operatorUsed = sender.tag
performingMath = true
} else if sender.tag == 11 {
if operatorUsed == 12 {
Label.text = String(firstNumber + secondNumber)
}
if operatorUsed == 13 {
Label.text = String(firstNumber - secondNumber)
}
if operatorUsed == 14 {
Label.text = String(firstNumber * secondNumber)
}
if operatorUsed == 15 {
Label.text = String(firstNumber / secondNumber)
}
}
}
}
I expect the that I can input many values as possible after I used a math operator (ex. +-*/)

Answer 1

When you update the label's text when performingMath is true, you just assign the new value instead of adding the value to the existing one (see line 3)
#IBAction func Numbers(_ sender: UIButton) {
if performingMath {
Label.text = String(sender.tag - 1) // !! HERE !!
secondNumber = Double(Label.text!)!
performingMath = true
} else {
Label.text = Label.text! + String(sender.tag - 1)
secondNumber = Double(Label.text!)!
}
}
This should perform the same action as when performingMath is false, so you just need to update this line with:
Label.text = Label.text! + String(sender.tag - 1)