RLE encoding in C++

rle.cpp

template< typename C >
string rle( const C& input )
{
   stringstream out;
   typedef C::const_iterator::value_type el_tyle;
   pair<C::const_iterator,C::const_iterator> bounds;
   bounds.second=input.begin();

   while( (bounds.first=bounds.second)!=input.end() )
   {
       bounds.second=find_if(
                               bounds.first, input.end(),
                               bind1st(not_equal_to<el_tyle>(), *bounds.first)
                            );
       out << distance(bounds.first,bounds.second) << *bounds.first;
   }
   return out.str();
}