I need help on the code challenge in swift 3 collections and control flow with loops i'm stuck

Question

It's asking me to compute the value of the sum inside the while loop by using the value of counter as an index value, and by retrieving values from inside the array and adding them to the sum. How would I write that? I tried retrieving the whole array and adding it and I also tried adding each integer separately and neither were correct.
```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
   print(counter)
   }
```

Michael Afanasiev · Accepted Answer

Hi Mackenzie!
Your code is almost there! -- Let's see what the challenge is asking us; 
Step 1: Create a while loop. The while loop should continue as long as the value of counter is less than the number of items in the array. (Hint: You can get that number by using the count property)
"...should continue as long as the value of counter is less than..." so we write our loop like so:
swift
while counter < numbers {
}

"...You can get that number by using the count property..." - so we have a count property that we can use, let's add it to numbers:
swift 
while counter < numbers.count {
}

And we'll increment the counter variable not for the loop to run infinitely:
swift
while counter < numbers.count {
       counter += 1
} 
  
Step 2: Using the value of counter as an index value, retrieve each value from the array and add it to the value of sum. 
OK, so counter becomes our index value and we can use it to "call out" the numbers from the array like so:
swift 
while counter < numbers.count {
    // we use counter as the index value and retrieve it from the numbers array
    sum += numbers[counter]
    counter += 1
}

I hope you find the step-by-step useful! ✊

james south · Answer

just a few things. you don't need to print anything here. the logic is simply to use your counter as the index to the array, and progressively add each element to sum, THEN increment your counter as the last step in the loop. you can get the value at a certain index with myArray[index]. then you just need to change <= to < to get it to pass.

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Mackenzie Milroy

Mackenzie Milroy

I need help on the code challenge in swift 3 collections and control flow with loops i'm stuck

2 Answers

Michael Afanasiev

Michael Afanasiev

james south

james south