Passing textFielddata with prepareForSegue as a number and not a string - xcode

Question

I am having trouble with the whole string int thing.
I have managed to figure out how to convert each string to a number, however it returns as an optional and when I try to do anything with it I get nil.
My goal is to take 4 inputs from the user.
Each input textField is on separate view controllers.
Each view controller is fed data from variables passed from the view controller before it, using segue prepareForSegue.
Now I get to the last view controller and all the data passes fine, the problem is I cannot do any math with the values held in the variables since they are Strings.
Even after doing the conversion with .int() I cannot do math with them.
This is the last view controller classfile code:
class splitTheBillAmountViewController: UIViewController {
// capture passed data from previous View Controller
var numOfGuests = ""
var subTotalAmount = ""
var taxAmount = ""
var tipAmount = ""
#IBOutlet weak var dynamicTotal: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
println("Split The Bill!”)
// output variables data
println(numOfGuests)
println(subTotalAmount)
println(taxAmount)
println(tipAmount)
// store variables to new name
let string1 = numOfGuests
let string2 = subTotalAmount
let string3 = taxAmount
let string4 = tipAmount
// conversions
let guestNumber : Int? = string1.toInt()
let subTotalNumber : Int? = string2.toInt()
let taxAmountNumber : Int? = string3.toInt()
let tipNumber : Int? = string4.toInt()
// visual to see if numbers are converted .int()
println("\(guestNumber)")
println("\(subTotalNumber)")
println("\(taxAmountNumber)")
println("\(tipNumber)")
// store data to variable
let fTotal : Int? = (guestNumber)
// Update label with total
self.dynamicTotal.text = “fTotal"
// Do any additional setup after loading the view.
}
How can I do math with these variables?
I just need to add them up and divide by var numOfGuests

Answer 1

I'm not sure you want to use Ints for all these values, but that aside I ran this code:
var numOfGuests = "2"
var subTotalAmount = "25"
var taxAmount = "3"
var tipAmount = "2"
let string1 = numOfGuests
let string2 = subTotalAmount
let string3 = taxAmount
let string4 = tipAmount
let guestNumber : Int? = string1.toInt()
let subTotalNumber : Int? = string2.toInt()
let taxAmountNumber : Int? = string3.toInt()
let tipNumber : Int? = string4.toInt()
println("\(guestNumber)")
println("\(subTotalNumber)")
println("\(taxAmountNumber)")
println("\(tipNumber)")
it printed:
Optional(2)
Optional(25)
Optional(3)
Optional(2)
I then modified the print statements to:
println("\(guestNumber!)")
println("\(subTotalNumber!)")
println("\(taxAmountNumber!)")
println("\(tipNumber!)")
It printed:
2
25
3
2
In neither case was the output nil. I think you want to look at how your original strings are getting set. Maybe they're never getting reset from "".
BTW, back to the use of Int types for the calculations, I think you really want to use Float type, not Int.
This code:
var subTotalAmount = "25.15"
let string2 = subTotalAmount
var subTotalNumber = (string2 as NSString).floatValue
println("\(subTotalNumber)")
prints:
25.15
EDIT:
I played with copying your code, and I think you know that you have a typo that the compiler should warn you about. Once I fixed the typo, however I was getting a nil. I got this code to work:
var subTotalAmount = "25.15"
let string2 = subTotalAmount
var subTotalNumber = (string2 as NSString).floatValue
println("\(subTotalNumber)")
let text = NSString(format: "%.2f", subTotalNumber)
println(text)
This prints:
25.15
25.15
EDIT2:
Assuming you have all the numbers as floats, the total bill would be:
var fTotal:Float = subTotalNumber + taxAmountNumber + tipNumber
var costPerGuest:Float = fTotal / guestNumber
let fTotalText = NSString(format: "%.2f", fTotal)
let costPerGuestText = NSString(format: "%.2f", costPerGuest)