CODEWITHSUNDEEP
swiftswift-playground
user1898829
user1898829

Reputation: 3527

How to write method to calculate average in Swift-playground

In swift I'm trying to write a method to calculate the average. Using the method below if i type average(5,10,15) I get infinity displayed in the swift-playforund

func average(numbers: Int...) -> Double {
    var sum = 0
    var count = 0
    for number in numbers {
        sum += number
    }
    var  ave : Double = Double(sum) / Double(count)
    return ave
}

Upvotes: 9

Views: 23213

Answers (10)

John Scalo
John Scalo

Reputation: 3401

import Accelerate

let avg = vDSP.mean(array)

This will be at least 50x faster than all other solutions posted so far.

Upvotes: 11

Maria Zverina
Maria Zverina

Reputation: 11173

While others have already pointed out the missing count variable, it is worth noting that you can do the average even more elegantly by using closures as follows:

func averagec(numbers:Int...) -> Double {
    return Double(numbers.reduce(0,combine:+))/Double(numbers.count)
}

Edited for Swift 4:-

func averagec(numbers:Int...) -> Double {
    return Double(numbers.reduce(0,+))/Double(numbers.count)
}

Upvotes: 21

wcochran
wcochran

Reputation: 10896

Swift 3, functional style 

func average(numbers: Int...) -> Double {
    assert(numbers.count > 0)
    return numbers.reduce(0, {$0 + Double($1)})/Double(numbers.count)
}

Upvotes: 1

Vineesh TP
Vineesh TP

Reputation: 7973

check this method.

func averageOf(numbers:Int...)->Float{

    var sum = 0
    for number in numbers{
        sum += number
    }
    return Float(sum)/Float(numbers.count)
}

averageOf(20,10,30)

Upvotes: 0

GarlicFries
GarlicFries

Reputation: 8323

It's so much easier with just a straightforward call to reduce:

let array = [1.0,2.0,3.0]
var average = array.reduce(0.0) {
    return $0 + $1/Double(array.count)
}
// average = 2.0

Upvotes: 35

james Burns
james Burns

Reputation: 864

Here's what I did:

func getAverage(nums: Double...) ->Double
{
    var temp = 0.0
    for num in nums
    {
        temp+=num
    }
    let div = Double(nums.count)
    var average = temp/div
    return average
}
getAverage(21,34.5,28,79)

Note that I'm accepting Doubles as input, not just Ints. I'm being a little verbose at the end, but I was trying for readable code. I probably could have just returned:

 return temp/Double(nums.count)

at the end and saved a few lines of code.

Upvotes: 1

Bill
Bill

Reputation: 45466

You're getting infinity because count is always 0 - it's never incremented. So the ave variable is always going to be equal to some number over 0, which is a divide by zero error.

Either use countElements(numbers) or increment count on each iteration through the loop.

Upvotes: 1

Jens Wirth
Jens Wirth

Reputation: 17460

You can use the count property of the array:

func average(numbers: Int...) -> Double {
    var sum = 0
    for number in numbers {
        sum += number
    }
    var  ave : Double = Double(sum) / Double(numbers.count)
    return ave
}

Upvotes: 23

iPatel
iPatel

Reputation: 47099

Just write count = count +1 in your for loop.

Such like,,,

.
.
.
for number in numbers 
{
  sum += number
  count = count +1
}
.
.

And now function by

var avg:Double = average(5,10,15)
println(avg)

Upvotes: 3

Anton Gogolev
Anton Gogolev

Reputation: 115829

You forget to increment count in the inner loop.

Upvotes: 2

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