Re: Occurence problem: different ideas

In article <1147023768.882586.288170@y43g2000cwc.googlegroups.com>,
 "utab" <umut.tabak@gmail.com> wrote:


You could have made it much harder on yourself and not used vector. Why
are you willing to use vector but not map or set?


Here's one solution:

struct word_count
{
   word_count( string w, int c ): word( w ), count( c ) { }
   string word;
   int count;
};

struct word_is : unary_function<word_count, bool >
{
   string word;
   word_is( string w ): word( w ) { }
   bool operator()( word_count wc ) const
   {
      return wc.word == word;
   }
};

   template < typename container >
void count_input_words( istream& is, container& c )
{
   string s;
   while ( is >> s ) {
      word_count wc( s, 1 );
      typename container::iterator it =
                           find_if( c.begin(), c.end(), word_is( s ) );
      if ( it == c.end() )
         c.push_back( wc );
      else
         ++it->count;
   }
}

ostream& operator<<( ostream& os, word_count wc )
{
   return os << wc.word << "\t" << wc.count;
}

int main()
{
   vector<word_count> result;
   count_input_words( cin, result );
   std::cout << "WORDS\tOCCURENCE#\n";
   copy( result.begin(), result.end(),
                           ostream_iterator<word_count>( cout, "\r" ) );
}

Seems pretty easy to understand, we have only one function with a
Cyclomatic Complexity over 1, and it only has a CC of 3. Compare that to
your code with a CC of 8.

Of course my code doesn't sort the words. That may be part of the
requirements, and would probably also speed up the algorithm by reducing
search time.

It's a simple change. Just change out "word_is" for a StrictWeakOrdering
comparison functor, and switch out the "find_if" for "lower_bound". That
and a minor change to the "if" statement and you are good to go. (I'll
leave it as an exorcise for the reader to implement though. :-)