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

Posted by Billy Potts
Billy Potts
Courses Plus Student 2,344 Points

how to get the values from an array to add up

Now that we have the while loop set up, it's time to compute the sum! Using the value of counter as an index value, retrieve each value from the array and add it to the value of sum.

For example: sum = sum + newValue. Or you could use the compound addition operator sum += newValue where newValue is the value retrieved from the array.

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

// Enter your code below
while counter < numbers.count { print(counter)
                counter++
                }

sum = counter + numbers[:8]
Alexander Davison
Alexander Davison
65,469 Points

You got it all right, but you just need to insert that last line of code into the while loop above the counter++:

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

// Enter your code below
while counter < numbers.count {
    sum = counter + numbers[:8]
    counter++
}

Also, slices (you did numbers[:8]) give you an array, not a number. Instead, try this. It goes through every element in the array and adds it to the sum. I tested this, so it works.

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++
}

Hope it helps! ~xela888