not work round Float for swift 4

Question

let value:Float = 5.678434
let roundedValue = round(value * 100) / 100

roundedValue Float 5.6784339

how to get 5.67 or 5.68?

The result can be different from 5.68 due to the limited precision of binary floating point numbers (see https://stackoverflow.com/questions/588004/is-floating-point-math-broken), but is should be close to 5.68 and not 5.6784339. Are you sure that you print the correct variable? — Martin R, Dec 28 '17 at 07:52
I am getting 5.68 here too, do not know if you are checking it correctly. Also, maybe check with `roundf` instead of `round`. — Oxthor, Dec 28 '17 at 07:53
If you want properly rounded to nth decimal position, you should use [`Decimal`](https://developer.apple.com/documentation/foundation/decimal), instead of `Float`. — user28434'mstep, Dec 28 '17 at 08:35

score 1 · Answer 1 · answered Dec 28 '17 at 12:14

1

extension Float {
    func rounded(toPlaces places:Int) -> Float {
        let divisor = pow(10.0, Float(places))
        return (self * divisor).rounded() / divisor
    }
}

let floatNumber:Float = 3.67565676

print(floatNumber.rounded(toPlaces: 2))

//prints 3.68

answered Dec 28 '17 at 12:14

Sameh Salama

765
1
7
17

This is what OP already does, only written as an extension method. Your answer does not explain the problem, or how your code solves it. – Martin R Dec 28 '17 at 18:25
the question was pretty clear “how to get 5.67 or 5.68?” – Sameh Salama Dec 28 '17 at 18:51

not work round Float for swift 4

1 Answers1