Round up an integer to multiple of 3

Question

I would like to round an integer up to its closest multiple of 3. Example:

var numberOne = 2
var numberTwo = 7

• numberOne rounded up would equal 3
• numberTwo rounded up would equal 9

I do not want it to ever round down.

Any ideas? Thanks

Answer 1

My 2 ct:

func roundUp(value: Int, divisor: Int) -> Int {
    let rem = value % divisor
    return rem == 0 ? value : value + divisor - rem
}

Answer 2

I got this working in a Playground:

import Foundation

func roundToThree(value: Int) -> Int{
    var fractionNum = Double(value) / 3.0
    let roundedNum = Int(ceil(fractionNum))
    return roundedNum * 3
}

roundToThree(2)
roundToThree(7)