How do I efficiently remove_if only a single element from a forward_list?

Question

Well I think the question pretty much sums it up. I have a forward_list of unique items, and want to remove a single item from it:

std::forward_list         


        

Answer 1

FWIW, here's another short version

template< typename T, class Allocator, class Predicate >
bool remove_first_if( std::forward_list< T, Allocator >& list, Predicate pred )
{
    auto oit = list.before_begin(), it = std::next( oit );
    while( it != list.end() ) {
        if( pred( *it ) ) { list.erase_after( oit ); return true; }
        oit = it++;
    }
    return false;
}