我试图使一个计算器的增长率(双),将结果四舍五入到最近的整数,并从那里重新计算,如:

let firstUsers = 10.0
let growth = 0.1
var users = firstUsers
var week = 0


while users < 14 {
    println("week \(week) has \(users) users")
    users += users * growth
    week += 1
}

但到目前为止我还不能。

编辑 我是这样做的:

var firstUsers = 10.0
let growth = 0.1
var users:Int = Int(firstUsers)
var week = 0


while users <= 14 {
    println("week \(week) has \(users) users")
    firstUsers += firstUsers * growth
    users = Int(firstUsers)
    week += 1
}

虽然我不介意它总是四舍五入,但我不喜欢它,因为firstUsers必须成为一个变量,并在整个程序中改变(为了进行下一次计算),这是我不希望发生的。


当前回答

这是我想到的最简单的方法

let weightValue = 143.69
print("Rounded off weight value = \(Int(weightValue))")

替代方法:

print("Rounded off weight value = \((String(format: "%.0f", sender.value)))")

其他回答

你也可以扩展FloatingPoint在Swift 3如下:

extension FloatingPoint {
    func rounded(to n: Int) -> Self {
        let n = Self(n)
        return (self / n).rounded() * n

    }
}

324.0.rounded(to: 5)   // 325

斯威夫特3

var myNum = 8.09
myNum.rounded() // result = 8 and leaves myNum unmodified

斯威夫特3: 如果你想四舍五入到某个数字,例如5.678434 -> 5.68,你可以将round()或roundf()函数与乘法组合:

let value:Float = 5.678434
let roundedValue = roundf(value * 100) / 100
print(roundedValue) //5.68

这是我想到的最简单的方法

let weightValue = 143.69
print("Rounded off weight value = \(Int(weightValue))")

替代方法:

print("Rounded off weight value = \((String(format: "%.0f", sender.value)))")

一个非常简单的解决方案对我很有效:

  if (62 % 50 != 0) {
      var number = 62 / 50 + 1 // adding 1 is doing the actual "round up"
  }

数字包含值2