swift - cannot invoke avgArray with an argument list of int -

i'm new swift, , start learn language following the swift programming language. in book, there exercise question ask me write function calculate average of array. here code:

func avgarray(elements: int...)->double{ var avg:double = 0 var sum = 0 var count = 0 element in elements {     sum += element     count += 1 } avg = double(sum) / double(count) return avg }  let numberlist = [2,3,6,7,2,7,0,9,12] let average = avgarray(numberlist) 

i don't know why can't pass array function. also, there way besides using count variable keep track of number of elements in array?

i don't know why can't pass array function.

your elements not array, variadic parameter. change

func avgarray(elements: [int])->double{ 

and should go.

is there way besides using count variable keep track of number of elements in array?

absolutely. count property of array itself. can use in code this:

avg = double(sum) / double(elements.count)