template <class ForwardIterator, class T>    
void fill(ForwardIterator first, ForwardIterator last, const T &value) {          
    for(; first != last; ++first)                                                 
        *first = value;                                                           
}                                                                                 
template <class OutputIterator, class Size, class T>                              
OutputIterator fill_n(OutputIterator first, Size n, const T &value) { 
    for(; n > 0; --n, ++first)                                                    
        *first = value;                                                           
    return first;                                                                  
}