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iOS Swift 2.0 Collections and Control Flow Control Flow With Loops Working with Loops

Posted by Haris Periorellis
Haris Periorellis
461 Points

Why is this wronge?

Why is this wronge?

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

// Enter your code below
while counter < 7 { print (7) 7++ }

2 Answers

Steve Hunter
Steve Hunter
57,712 Points

Hi Haris,

You want to use the while loop to iterate through each element of the array. At each step, add the element into the variable, sum.

First, you need to set the limits of the while loop. This is done using counter; while counter is less than the number of elements in numbers you want to loop. Else, you want to stop. Inside the loop, increment counter using the ++ operator.

Then, access the array by using the counter to point at the current element - you can use square bracket notation to access that element, like numbers[counter]. Add that value into sum. Something like:

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++
}

I hope explains the challenge for you.

Steve.

Roberto Pando
Roberto Pando
9,486 Points
Roberto Pando
Roberto Pando
9,486 Points

For the condition of the while loop instead of explicitly stating the count of the array you can do just that with the syntax .count, suppose in a real project you decide to add another number then you would have to change the condition as well, therefore .count is the best option. After that you have to increment counter++ otherwise the loop would continue forever because the condition is never going to be met. the correct code looks like this.

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

}