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Programming Challenge: Are You a Swift Ninja? Part 2

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1

Do you consider yourself a Swift Ninja? Take our programming challenge! Beginners are also welcome to follow through and learn the craft.

This is a companion discussion topic for the original entry at https://www.raywenderlich.com/2328-programming-challenge-are-you-a-swift-ninja-part-2
2

I’m surprised no one posted anything…

Alternative solution for #5

func reverseString(string: String) {
    guard !string.isEmpty else { return }
    print(string.substringFromIndex(string.endIndex.predecessor()), terminator: string.startIndex < string.endIndex.predecessor() ? "" : "\n")
    reverseString(string.substringToIndex(string.endIndex.predecessor()))
}

func altReverseString(string: String) -> String {
    guard !string.isEmpty else { return "" }
    return string.substringFromIndex(string.endIndex.predecessor()) + altReverseString(string.substringToIndex(string.endIndex.predecessor()))
}

Challenge #6:

func * (lhs: String, rhs: Int) -> String {
    guard rhs > 0 else { return "" }
    return lhs + (lhs * (rhs-1))
}

Challenge #7:

func isSuccess(success: Bool) -> String {
    return ["error", "success!"][Int(success)]
}

print(isSuccess(doWork()))

Final:

func countHand(deck: [Card]) -> Int {
    return deck.enumerate().reduce(0) {
        guard $1.index < deck.count - 1 else { return $0 }
        if case Rank.Num(5) = $1.element.rank, case Rank.Ace = deck[$1.index+1].rank where $1.element.suit == .Diamonds {
            return $0 + 100
        } else if case Rank.Num(let num) = deck[$1.index+1].rank where $1.element.suit == .Hearts && [3, 5, 7, 9].contains(num) {
            return $0 + num * 2
        }
        return $0
    }
}
3

Hey bossagroove I’m glad you’re enjoying the “ninja” articles. They are about 2 years old (when Swift was in early beta) and I this was before the last big update to the forums on raywenderlich.com so I think the comments are somewhere on the forums, which was the old system to track comments per article.

4

Here is my solution for #5 I know i use variables but in my case it makes the code a little bit cleaner.

 extension String {
        func reversed() -> String {
            return reverseString(text: self, lastCharacters: "")
        }
    
    fileprivate func reverseString(text:String, lastCharacters: String) -> String {
        if let lastCharacter = text.characters.last {
            let subText = text.substring(to: text.index(text.endIndex, offsetBy: -1))
            return reverseString(text: subText, lastCharacters: lastCharacters + String(lastCharacter))
        } else {
            return lastCharacters
        }
    }
}
"Reverse Me".reversed()
5

Challenge #6
my solution

func *(lhs: Character, rhs: Int) → String {
return rhs == 0 ? “” : String(lhs) + (lhs * (rhs - 1))
}

6

I know it is late, but still wanted to paste my solution to the final challenge.

7

This tutorial is more than six months old so questions are no longer supported at the moment for it. Thank you!