不能在swift中使用“地板”

Question

var viewSize = Double(viewersView.frame.size.width)
var itemSize = Double(boxSize + viewerHorizontalPadding)
self.maxViewers = floor(viewSize / itemSize) //should be Int

I get an error that says:

No "floor" candidates produce expected contextual result type "Int"

I imported Darwin.

Answer 1

floor takes a Double and returns another Double. If you want it to be an Int (to match self.maxViewers , you must convert it explicitly: Int(floor(viewSize / itemSize)) .

Answer 2

Use round(_:) method or rounded(_:)

round(_:) ]: Rounds the value to an integral value using the specified rounding rule. rounded(_:) : Returns this value rounded to an integral value using the specified rounding rule

var w1 = 6.5
w1.round()
// w1 == 7.0

// Equivalent to the C 'round' function:
var w = 6.5
w.round(.toNearestOrAwayFromZero)
// w == 7.0

// Equivalent to the C 'trunc' function:
var x = 6.5
x.round(.towardZero)
// x == 6.0

// Equivalent to the C 'ceil' function:
var y = 6.5
y.round(.up)
// y == 7.0

// Equivalent to the C 'floor' function:
var z = 6.5
z.round(.down)
// z == 6.0