Difference between else and elsif in this peice of code that hails different results? : in this code here if I put longest_word("my name is bobby li") it returns "bobby" if it is elsif but if i choose else it will return "li". Can someone explain? 
 
        def longest_word(sentence)
        words = sentence.split(" ")

     longest_word = nil

     word_idx = 0
    while word_idx < words.length
    current_word = words[word_idx]

    if longest_word == nil
      longest_word = current_word
    **elsif** longest_word.length < current_word.length
      longest_word = current_word
    end

    word_idx += 1
    end
    return longest_word
    end

