CODEWITHSUNDEEP
swiftaverage
InVaDeR
InVaDeR

Reputation: 3

can't do division function in swift

I'm making the average function assignment from swift tutorial. When I write code like this:

func AVG(numbers: Int...) -> Double {
var i=0, sum=0; var avg: Double
for number in numbers {
    i+=1
    sum+=number
    avg = sum/i
}
return avg
}

let Average = AVG(numbers: 3,4,5)
print (Average)

It displays an error message showing binary operator "/" cannot be applied to two int operands.

when i perform a simple division like 

let x = 5
let y = 2
let quo = x/y

it works.

What am I doing wrong in the function?

Upvotes: 0

Views: 108

Answers (2)

vadian
vadian

Reputation: 285160

There are two issues in the AVG function – btw. function names are supposed to start with a lowercase letter.

A playground displays clear error messages

  1. variable 'avg' used before being initialized

    Solution:

    var avg = 0.0

  2. cannot assign value of type 'Int' to type 'Double'

    Solution:

    avg = Double(sum) / Double(i)

PS: An alternative using the key-value coding operator @avg

func avg(numbers: Int...) -> Double {
    return (numbers as NSArray).value(forKeyPath: "@avg.self") as! Double
}

Upvotes: 0

Grzegorz Krukowski
Grzegorz Krukowski

Reputation: 19822

You declared avg as Double type.

numbers has Int as type, and i=0 makes it Int as well.

When you are doing sum/i it's Int/Int and you try to assign it to Double. Swift is not doing conversion automatically - it forces you to convert data types manually. You can fix it by simply converting both those variables to Double.

Keep in mind that you need to convert Int before doing division - otherwise result will cut the reminder as Int cannot have them. Credits to @martin

Also another problem is that if your numbers array is empty, you may try to return not initialized variable avg.

Working code below:

func AVG(numbers: Int...) -> Double {
    var i=0, sum=0; var avg: Double = 0
    for number in numbers {
        i+=1
        sum+=number
        avg = Double(sum)/Double(i)
    }
    return avg
}

let Average = AVG(numbers: 3,4,5)
print (Average)

Upvotes: 1

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