template< class T >  
\c{\fbox{bag<T>::count}}
int bag<T>::count(const T& e) const { iter<T> it = *this; T* p = 0; int cnt = 0; while ( p = it() ) if ( (T&) e == *p ) cnt++;
$(*)

return cnt; } template< class T >
\c{\fbox{bag<T>::map}
void bag<T>::map(T f(const T& e)) { iter<T> it = *this; T* p = 0; while ( p = it() ) *p = f(*p); }

slide: Bag operations