Rounding in Swift with round()
Updated answer
The round(someDecimal) is the old C style. As of Swift 3, doubles and floats have a built in Swift function.
var x = 0.8x.round() // x is 1.0 (rounds x in place)or
var x = 0.8var y = x.rounded() // y is 1.0, x is 0.8See my answer fuller answer here (or here) for more details about how different rounding rules can be used.
As other answers have noted, if you want to round to the thousandth, then multiply temporarily by 1000 before you round.