swift - 可变参数 - 编译器错误无法将类型 '[Int]' 的值转换为预期的参数类型 'Int'

Question

swift 新手。不确定为什么编译器会给出以下代码的错误。:

func addNumbers(numbers: Int ...) -> Int {
    var total : Int = 0
    for number in numbers {
        total += number
    }
    return total
}

func multiplyNumbers(numbers: Int ...) -> Int {
    var total : Int = numbers [0]
    for (index,number) in numbers.enumerate()  {
        if index == 0 {
            continue
        }
        total *= number
    }
    return total
}

func mathOperation(mathFunction: (Int ...) -> Int, numbers: Int ...) -> Int {
     return mathFunction(numbers)
}

错误:

error: cannot convert value of type '[Int]' to expected argument type 'Int' return mathFunction(numbers)

Answer 1

Swift 的可变参数并不那么容易使用。我会将参数类型更改为数组。这是一个有效的修复:

func addNumbers(numbers: [Int]) -> Int {
    var total : Int = 0
    for number in numbers {
        total += number
    }
    return total
}

func multiplyNumbers(numbers: [Int]) -> Int {
    var total : Int = numbers [0]
    for (index,number) in numbers.enumerate()  {
        if index == 0 {
            continue
        }
        total *= number
    }
    return total
}

func mathOperation(mathFunction: [Int] -> Int, numbers: Int ...) -> Int {
     return mathFunction(numbers)
}

print(mathOperation(multiplyNumbers,numbers: 3,24))

这将打印出 72