HowTo create template of a container (e.x. std::map)? - c++

Question

So, I had a simple working code, for example
template <typename T, typename VALUE>
VALUE mapAt(T key)
{
std::map<T, VALUE>::const_iterator item_i(MyMap.find(key))
, end_i(MyMap.end());
if (item_i == end_i)
{
throw std::exception("No such key!");
}
return (*item_i).second;
}
Question: is it possible to create a new template function without using std::map, but using different containers (e.x. std::map, std::multimap, ...), something like this:
template <class Container, typename T, typename VALUE>
VALUE mapAt(Container& MyMap, T key)
{
Container<T, VALUE>::const_iterator item_i(MyMap.find(key))
, end_i(MyMap.end());
/* ... */
}
Problem: when i'm tring to use it, like:
std::map<int, char> my_map;
char ch = mapAt<std::map<int, char>(), int, char>(my_map, 123); // C2664 error
compiler gaves me an error:
main.cpp(119) : error C2664: 'mapAt' :
cannot convert parameter 1 from
'std::map<_Kty,_Ty>' to
'std::map<_Kty,Ty> (_cdecl &)' 1>
with 1> [ 1>
_Kty=int, 1> _Ty=char 1> ] 1> No user-defined-conversion
operator available that can perform
this conversion, or the operator
cannot be called

Answer 1

You can write something like this:
template <class Container>
typename Container::mapped_type mapAt(Container& MyMap, typename const Container::key_type& key)
{
typename Container::const_iterator iter = MyMap.find(key);
return iter->second;
}
int main()
{
std::map<int, char> my_map;
char ch = mapAt(my_map, 123);
}