HashTableValueForKey.swift

struct HashTable<Key: Hashable, Value> {
    
    typealias Bucket = [HashElement<Key, Value>]
    
    var buckets: [Bucket]
    
    init(capacity: Int) {
        assert(capacity > 0)
        buckets = Array<Bucket>(repeatElement([], count: capacity))
    }
    
     func index(for key: Key) -> Int {
        var divisor: Int = 0
        for key in String(describing: key).unicodeScalars {
            divisor += abs(Int(key.value.hashValue))
        }
        return abs(divisor) % buckets.count
    }
    
    func value(for key: Key) -> Value? {
        let index = self.index(for: key)
        
        for element in buckets[index] {
            if element.key == key {
                return element.value
            }
        }
        return nil
    }
}