Function Keeps Subtracting Instead Of Dividing

Question

Below is the code that I have

let interestone = 0.0485
let interesttwo = 0.0625
let interestthree = 0.0725
let months: Double = Double(leasingTextField.text!)!
if months <= 24 {
    rentePercentLabel.text = String(format: "%.2f%%", 4.85)
    renteLabel.text = String(interestone * (price - payouttwo) / 12 * months)
    totalCostsLabel.text = String(price + (interestone * (price - payouttwo) / 12 * months))
    leasingafgiftLabel.text = String(payouttwo + restsumtwo +
        (interestone * (price - payouttwo) / 12 * months) / months)
}

The line below is the one that is giving me trouble, because instead of performing the two equations and then dividing the months last, what happens is that payouttwo and restsumtwo get added and then the next part is added to that.

leasingafgiftLabel.text = String(payouttwo + restsumtwo + 
    (interestone * (price - payouttwo) / 12 * months / months))

I tried that and got this error: Cannot use optional chaining on non-optional value of type 'Double' — Julian, Jun 11 '18 at 18:50
Your troublesome line is acting like it's supposed, doing the calculations in parenthesis before the rest. You should add or restructure your parenthesis in order to effect the order you desire. — Owen Hartnett, Jun 11 '18 at 19:05

Anamika · Accepted Answer · 2018-06-11T19:03:28.707

I think you can try this...

let interestone = 0.0485
let interesttwo = 0.0625
let interestthree = 0.0725
let months: Double = Double(leasingTextField.text!)!
if months <= 24 {
    rentePercentLabel.text = String(format: "%.2f%%", 4.85)
    let renteLabelValue = interestone * (price - payouttwo) / 12 * months
    renteLabel.text = String(renteLabelValue)
    totalCostsLabel.text = String(price + (interestone * (price - payouttwo) / 12 * months))
    leasingafgiftLabel.text = String((payouttwo + restsumtwo + renteLabelValue) / months)
}

What I understood from that line was it was not able to calculate values as you were expecting, We can calculate a part of equation before itself and use that in the actual equation.

Code-only answers are not helpful. Please update your answer to explain what was wrong and how your answer fixes the issue. — rmaddy, Jun 11 '18 at 18:52

Function Keeps Subtracting Instead Of Dividing

1 Answers1