Abstracted average function in swift

average.swift

extension Sequence where Element: BinaryFloatingPoint {
    func average() -> Element {
        return abstractAverage(sequence: self, sum: +, div: /)
    }
}
extension Sequence where Element: SignedInteger {
    func average() -> Element {
        return abstractAverage(sequence: self, sum: +, div: /)
    }
}

func abstractAverage<T :ExpressibleByIntegerLiteral, S :Sequence> (sequence: S, sum: (T, T)->T, div: (T, T)->T, zero: T = 0, one: T = 1) -> T where S.Element == T  {
    var i: T = zero
    var total: T = zero
    
    for value in sequence {
        total = sum(total, value)
        i = sum(i, one)
    }
    
    return div(total, i)
}

[1.0, 2.2, 3.0].average()
[1, 2, 3].average()