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

Sam Belcher
Sam Belcher
3,719 Points
Posted by Sam Belcher
Sam Belcher
3,719 Points

Help with loops (specifically while loops)

Extremely confused

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

// Enter your code below

repeat {
sum.append( (numbers[1...7]))
} while counter < numbers.count
Harold Davis
Harold Davis
Courses Plus Student 14,604 Points

Not repeating while at the moment we are just setting the while loop and saying while the counter is less than the count add each number together.

you increment the counter by 1 after every iteration by using counter +=1

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
}

1 Answer

Joe Beltramo
PLUS
Joe Beltramo
Courses Plus Student 22,191 Points
Joe Beltramo
Joe Beltramo
Courses Plus Student 22,191 Points

In the code you provided, there are a few things that are happening here that might be causing you a problem.

As with almost all loops, they generally need a finite destination on knowing when to end the loop, otherwise they will run indefinitely.

In the challenge, they are looking for you to get the sum of all the numbers within the numbers array by using a while loop. Instead of appending items, try adding them with counter as your array index.

This means, you must also increment the counter within the loop. Since your counter will be consecutively growing, it will give the while expression a chance to finish and reach an end.

while counter < numbers.count

One problem you may have using a repeat...while loop though is that it will continue until counter is not less than the size of the numbers array. So if you want to still use the repeat...while loop, you will need to have your counter stop at 1 less than the size of the numbers array. i.e. numbers.count - 1 (Otherwise you will get an out of bounds error against your array)

Hope that helps!

Joe Beltramo
Joe Beltramo
Courses Plus Student 22,191 Points

Err, ignore the numbers.count - 1. I miscalculated.