Re: [boost] Re : BOOST_FOREACH like macro for map

Subject: Re: [boost] Re : BOOST_FOREACH like macro for map
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2009-10-20 17:28:36

AMDG

Stewart, Robert wrote:
> That is horribly inefficient: O(N).  Try this instead (untested):
>
>    template <class T, class U>
>    U const &
>    get_value(std::map<T,U> const & _map, T const & _key)
>    {
>       typename std::map<T,U>::const_iterator it(_map.find(_key));
>       if (it != _map.end())
>       {
>          return it->second;
>       }
>       throw std::domain_error("key not found");
>    }
>
> That is O log(N).
>   

Wouldn't it be better to return a null pointer instead of throwing an 
exception?

In Christ,
Steven Watanabe