By Kevin


2016-02-13 17:35:53 8 Comments

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
            var myInt2: Int? = Int(radien.text!)
            let pi = 3.1415926
            let lutning = 360


            let result = (Double(myInt! / lutning) * Double(pi))
            svar2.text = "\(result)"
        }

3 comments

@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. E.g.

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

Or define

let lutning = 360.0

and then

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

And, BTW, I'd suggest using M_PI rather than defining your own pi.

let result = Double(myInt!) / lutning * M_PI

@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!)
let myInt2 = Int(radien.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))

Related Questions

Sponsored Content

23 Answered Questions

[SOLVED] @selector() in Swift?

17 Answered Questions

[SOLVED] How do I call Objective-C code from Swift?

  • 2014-06-02 20:05:42
  • David Mulder
  • 275054 View
  • 940 Score
  • 17 Answer
  • Tags:   objective-c swift

31 Answered Questions

[SOLVED] Is floating point math broken?

20 Answered Questions

[SOLVED] #pragma mark in Swift?

  • 2014-06-03 14:05:56
  • Arbitur
  • 214592 View
  • 915 Score
  • 20 Answer
  • Tags:   swift

15 Answered Questions

[SOLVED] Swift for loop: for index, element in array?

  • 2014-06-04 03:19:21
  • thinker3
  • 407315 View
  • 739 Score
  • 15 Answer
  • Tags:   arrays swift

25 Answered Questions

[SOLVED] How do I make an attributed string using Swift?

16 Answered Questions

[SOLVED] #ifdef replacement in the Swift language

9 Answered Questions

[SOLVED] Swift Beta performance: sorting arrays

1 Answered Questions

[SOLVED] Correcting floating math broken by multiplying, is it ok?

  • 2014-05-07 16:16:43
  • Prosto Trader
  • 112 View
  • 3 Score
  • 1 Answer
  • Tags:   javascript math

Sponsored Content