On Apr 6, 6:46 am, Rui Maciel <rui.mac...@gmail.com> wrote:
In order to avoid wasting resources populating a map with
useless key:value pairs, is there a clean, unencumbered way
to get the value associated with a given key without being
forced to insert new elements or even resort to multiple
lines of code? The closest thing I saw was the map::find()
method, but I believe that ends up forcing to write code to
compare the given iterator to map::end() and, if it matches,
return a default value.
Is there a simpler way to do this?
I find these two functions (including their general semantics)
and variants of them exceedingly useful
template < class K, class V, class C, class A>
V
getOrZero (
std::map<K,V,C,A> const & m
, K const & k
) {
typename std::map<K,V,C,A>::const_iterator i = m.find(k) ;
return i != m.end() ? i->second : V() ;
}
template < class K, class V, class C, class A>
V &
getOrMake (
std::map<K,V,C,A> & m
, K const & k
) {
return m[k] ;
}
for all types of containers including STL and custom ones.