Iterator over a map of generic vectors.

Eric Lance eric.lance@gmail.com
Fri Sep 8 22:28:00 GMT 2006


Hi all,

I'm trying to figure out if this is a bug or "feature". In a generic
function, I want to declare an iterator over a map whose values are
generic vectors. However, I get a syntax error whenever I try to
declare this particular kind of iterator. The code snippet below
should illustrate what I mean better:

template<typename T>
void func()
{
    map< int, vector<T> > m;             //we want an iterator over m.
    map< int, vector<T> >::iterator i;      //this doesn't compile
    map< int, vector<int> >::iterator k;   //but this does
}

On GCC 4.1.0 (Suse) and GCC 3.4.4 (FreeBSD) it throws the following
syntax error:
      Test.cpp: In function 'void func()':
      Test.cpp:16: error: expected `;' before 'i'

The code snippet will compile cleanly on MS visual studio.  It also
seems illogical that I can declare map "m", but it is illegal to
declare the iterator " i". So, is this a "feature" or a bug?


I'm not subscribed to the list, so please CC me in on any replies.

Thanks,
Eric


PS As a workaround, I changed the declaration to the following, which
seems to work:
    typeof(m.iterator) i=m.begin();



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