Re: Typedef'ing a subtype of a template

From:

=?ISO-8859-1?Q?Ney_Andr=E9_de_Mello_Zunino?= <zunino@inf.ufsc.br>

Newsgroups:

comp.lang.c++

Date:

Thu, 22 Nov 2007 07:15:34 -0200

Message-ID:

<fi3hbp$1b6$1@aioe.org>

red floyd wrote:

I see nothing wrong with your code. Is this the entire fragment? What
compiler are you using?

The compiler is g++ (GCC) 4.1.3. And here's a complete program. In its
current form, it _will_ compile. However, substituting the second
typedef for the third one will cause the compilation error when the
priority_queue /Word_Queue/ is instantiated in main().

#include <string>
#include <map>
#include <queue>
#include <vector>

namespace {
     using namespace std;

     typedef map<string, int> Word_Map;
// typedef Word_Map::value_type Word_Map_Pair;
     typedef pair<string, int> Word_Map_Pair;

     struct Word_Map_Pair_Comparator {
         bool operator()(const Word_Map_Pair& pair_1,
                         const Word_Map_Pair& pair_2) {
             return pair_1.second >= pair_2.second;
         }
     };

     typedef priority_queue<Word_Map_Pair, vector<Word_Map_Pair>,
             Word_Map_Pair_Comparator> Word_Queue;
}

int main(int argc, char* argv[]) {
     Word_Queue word_queue;
}

Thank you,

--
Ney Andr9 de Mello Zunino