numWords

  Write a method called numWords that takes a String
   as a parameter and that returns the number of words in the String.  By
   definition, words are separated by one or more spaces.  The table below
   shows several sample calls and the value that should be returned.

        Method Call                                             Value Returned
        ----------------------------------------------------    --------------
        numWords("how    many   words   here?")                       4
        numWords("to be or not to be, that is the question")          10
        numWords("  how  about  merry-go-round     ")                 3
        numWords(" !&$%--$$!!*()   foo_bar_baz   ")                   2
        numWords("x")                                                 1
        numWords("     ")                                             0
        numWords("")                                                  0

   Notice that words can contain punctuation marks.  Any non-empty sequence of
   non-space characters can be a word.  Also notice that there might be spaces
   at the beginning or end of the String.

   You may not construct any other objects to solve this problem (e.g., you
   can't use a Scanner or tokenizer).  You may assume that the String has no
   other whitespace characters such as tabs or newline characters.  Your method
   can pay attention just to spaces to decide how many words there are.