SOLVED: confusion with Repeat While loop

@teekachu

Jun '20

Hey Guys,

I am having a little difficulty fully understanding the repeat while loop concept. For example, I am trying to find the first 10 factors of 2 from the list of numbers 1 to 100. Easy right? I was able to do this easily with a for loop, which gave me answers [2, 4, 6, 8, 10, 12, 14, 16, 18, 20]

var evenNumber = [Int]()
var counter = 10

for num in 1...100 {
    if num % 2 == 0 {
        counter -= 1
        evenNumber.append(num)

        if counter == 0 {
            break
        }
    }
}

print(evenNumber)

However, I can't seem to achieve the same results with the repeat / while loop. The result gave me all 50 of the facotrs of 2 from 1 ... 100 instead of just the first 10 factors. What am I doing wrong?

var evenNumber = [Int]()

repeat {
    for num in 1...100 where num % 2 == 0 {
        evenNumber.append(num)
    }
} while evenNumber.count <= 10

print(evenNumber)

@delawaremathguy

Jun '20

hi,

although you have an outer repeat ... while loop, the first time the body of the loop executes, it runs its own loop -- from 1 to 100, appending lots of numbers to your evenNumber array. the outer loop runs exactly once.

what you really are trying to do is something like this:

var evenNumber = [Int]()
var num = 0
repeat {
    num += 1
    if num % 2 == 0 {
        evenNumber.append(num)
    }
} while evenNumber.count < 10 && num < 100 // note check here on the range for num
print(evenNumber)

hope that helps,

DMG

@teekachu

Jun '20

@delawaremathguy: THANK YOU DMG!! That REALLY HELPED! I am so happy.

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