Question

Swift 编译报错：Binary operator '+=' cannot be applied to operands of type 'Double' and '[Double]'

func arithmeticMean(numbers: Double...) -> Double {

var total: Double = 0

for number in numbers {

total += numbers

}

return total / Double(numbers.count)

}

arithmeticMean(1, 2, 3, 4, 5)

arithmeticMean(3, 8, 19)

求大神指点，找不到原因
找到原因了。。numbers多打了个s

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Answer 1

func arithmeticMean(numbers: Double...) -> Double {
var total: Double = 0
for number in numbers {
total += number
}
return total / Double(numbers.count)
}
arithmeticMean(1, 2, 3, 4, 5)
// returns 3.0, which is the arithmetic mean of these five numbers
arithmeticMean(3, 8, 19)
// returns 10.0, which is the arithmetic mean of these three numbers

Answer 2

类型不对，重新定义类型

追问

是在for循环内 number多打了个s，我看了半天才发现这个问题

追答

func arithmeticMean(numbers: Double...) -> Double {
var total: Double = 0
for number in numbers {
total += number
}
return total / Double(numbers.count)
}
arithmeticMean(1, 2, 3, 4, 5)
// returns 3.0, which is the arithmetic mean of these five numbers
arithmeticMean(3, 8, 19)
// returns 10.0, which is the arithmetic mean of these three numbers