#### [SOLVED] Math divison in Swift

By Kevin

I'm trying to make a math app with different equations and formulas but I'm trying to circle sector but i just wanted to try to divide the input value by 360 but when I do that it only says 0 unless the value is over 360. I have tried using String, Double and Float with no luck I don't know what I'm doing is wrong but down here is the code. I'm thankful for help but I have been sitting a while and searched online for an answer with no result I might have been searching with the wrong search.

``````if graderna.text == ""{
}
else{
var myInt: Int? = Int(graderna.text!)    // conversion of string to Int
let pi = 3.1415926
let lutning = 360

let result = (Double(myInt! / lutning) * Double(pi))
svar2.text = "\(result)"
}
`````` #### @Rob 2016-02-13 17:43:00

Your code is performing integer division, taking the integer result and converting it to a double. Instead, you want to convert these individual integers to doubles and then do the division. So, instead of

``````let result = (Double(myInt! / lutning) * Double(pi))
``````

You should

``````let result = Double(myInt!) / Double(lutning) * Double(pi)
``````

Note, `Double` already has a `.pi` constant, so you can remove your `pi` constant, and simplify the above to:

``````let result = Double(myInt!) / Double(lutning) * .pi
``````

Personally, I’d define `myInt` and `lutning` to be `Double` from the get go (and, while we’re at it, remove all of the forced unwrapping (with the `!`) of the optionals):

``````guard
let value = Double(text),
let value2 = Double(text2)
else {
return
}

let lutning: Double = 360
let result = value / lutning * .pi
``````

Or, you can use `flatMap` to safely unwrap those optional strings:

``````guard
let value = graderna.text.flatMap({ Double(\$0) }),
let value2 = radien.text.flatMap({ Double(\$0) })
else {
return
}

let lutning: Double = 360
let result = value / lutning * .pi
``````

(By the way, if you’re converting between radians and degrees, it should be 2π/360, not π/360.) #### @gnasher729 2016-02-13 17:42:58

You are dividing an Int by an Int.

Integer division rounds to the nearest integer towards zero. Therefore for example 359 / 360 is not a number close to 1, it is 0. 360 / 360 up to 719 / 360 equals 1. 720 / 360 to 1079 / 360 equals 2, and so on.

But your use of optionals is atrocious. I'd write

``````let myInt = Int(graderna.text!)

if let realInt = myInt, realInt2 = myInt2 {
let pi = 3.1415926
let lutning = 360.0

let result = Double (realInt) * (pi / lutning)
svar2.text = "\(result)"
}
`````` #### @Kevin 2016-02-13 18:43:53

Thanks for your timme and help aswell @gnasher729 #### @Cole 2016-02-13 17:42:27

In the line `let result = (Double(myInt! / lutning) * Double(pi))` you cast your type to `double` after dividing two integers so your result will always be zero. You have to make them doubles before division.

`let result = (Double(myInt!) / Double(lutning)) * Double(pi))`

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