Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

iOS Swift Collections and Control Flow Control Flow With Loops Working With Loops

Chris Miller
Chris Miller
2,186 Points

Not sure how to store each value of the array and add it. I'm getting wonky numbers.

// Challenge let numbers = [2,8,1,16,4,3,9] var sum = 0 var counter = 0

// Enter your code below while counter < numbers.count { counter += 1 let newValue = counter sum = sum + newValue } sum

Any help would be appreciated. Thanks!

loops.swift
let numbers = [2,8,1,16,4,3,9]
var sum = 0
var counter = 0

// Enter your code below
while counter < numbers.count {
  counter += 1
let newValue = counter
sum = sum + newValue
}

3 Answers

John Marley
John Marley
8,740 Points

Hi there,

Took me a while to work this out revisiting it but I'll break down the mistakes I made.

Initially did this, which failed...

// This resolution didn't take into account all values in array.
// I had to iterate within numbers.count - 1 otherwise I'd get an error

let numbers = [2,8,1,16,4,3,9]
var sum = 0
var counter = 0

// Enter your code below

while counter < numbers.count - 1 {
    counter += 1
    sum += numbers[counter]
}

The best way to access the values in the numbers array is to use subscripting syntax '[]' The following passed...

// Bearing in mind, arrays.count begins at 0
// sum = sum + numbers[whatever counter equals in this iteration]
// counter += 1 has to follow sum += numbers[counter]
// otherwise it skips the first value

let numbers = [2,8,1,16,4,3,9]
var sum = 0
var counter = 0

// Enter your code below

while counter < numbers.count {
    sum += numbers[counter]
    counter += 1
}
John Marley
John Marley
8,740 Points

The resolution to this question below is put more succinctly.

https://teamtreehouse.com/community/stuck-81

Chris Miller
Chris Miller
2,186 Points

Thanks for the detailed feedback.