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

Ryan Maneo
Ryan Maneo
4,342 Points
Posted by Ryan Maneo
Ryan Maneo
4,342 Points

Help with computing values and retrieving them

Task: "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."

Read the code below for my question.

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

// Enter your code below

while counter < 7 {
        sum += // What on earth do I put here?
        counter++

}

1 Answer

Keli'i Martin
Keli'i Martin
8,227 Points
Keli'i Martin
Keli'i Martin
8,227 Points

The answer is right there in the question. "Using the value of counter as an index value, retrieve each value from the array and add it to the value of sum."

In other words, you want to retrieve a value from the array. To do this, you need an index. So what you need to do is use the counter variable as that index. The result would look like this:

while counter < 7 {
        sum += numbers[counter]
        counter++
}

Hope this helps!

Ryan Maneo
Ryan Maneo
4,342 Points
Ryan Maneo
Ryan Maneo
4,342 Points

This helped, but I don't remember there being a lesson on Index's... was there?

Keli'i Martin
Keli'i Martin
8,227 Points
Keli'i Martin
Keli'i Martin
8,227 Points

Check out the Manipulating an Array video. Pasan talks about reading values from arrays using the index.