ios - 无法使用类型为 '^' 的参数列表调用 '($T27, IntegerLiteralConvertible)'

Question

func FindDistance(currentLatitude: Double, currentLongtitude: Double, compareLatitude: Double, compareLongtitdue: Double) -> Double {    
    var dlon = compareLongtitdue - currentLongtitude
    var dlat = compareLatitude - currentLatitude
    let WorldRadius = 6371

    var a = sin(dlat/2)^2 + cos(currentLatitude) * cos(compareLatitude) * sin(dlon/2)^2
    var c = 2 * atan2(sqrt(a), sqrt(1-a))
    var d = WorldRadius * c
}

println(FindDistance(11.583431, 104.920141, 11.584966, 104.918569))

There is an Error in Line in Variable "a". said 'Cannot Invoke '^' with an argument list of type '($T27, IntegerLiteralConvertible)'.

Answer 1

我猜您想使用 pow(x,y) 函数返回 x 的 y 次方。

所以为了访问这个函数你需要先导入Darwin然后重写代码如下:

import Darwin

func FindDistance(currentLatitude:Double, currentLongtitude:Double, compareLatitude:Double, compareLongtitdue:Double) -> Double {

        var dlon = compareLongtitdue - currentLongtitude
        var dlat = compareLatitude - currentLatitude
        let WorldRadius: Double = 6371

        var a = pow(sin(dlat/2), 2) + cos(currentLatitude) * cos(compareLatitude)  * pow(sin(dlon/2),2)
        var c = 2 * atan2( sqrt(a), sqrt(1-a) )
        var d = WorldRadius * c

        return d
    }