typedef inside class

Question

Can`t I perform typedef inside the class?

#include <vector>
using namespace std;
    class List {
    public:
           typedef int Data;
           class iterator;
           pair<iterator,bool> insert(const Data nodeId); //<-error
    private:
    class Node {
        typedef vector<NodeId> DepList;//<-error
    };
    }

I get an error missing type specifier - int assumed. Note: C++ does not support default-int

You should always be careful to see what line the error occurs on...I added `#include ` `using std::pair;` to the file and it compiled fine. — nneonneo, Oct 08 '12 at 19:23
please provide complete code, information on the build and the (uncut) output of any warnings (`-Wall -Wextra -pedantic ...`). — moooeeeep, Oct 08 '12 at 19:32

Kiril Kirov · Accepted Answer · 2012-10-08T19:34:38.190

1

You can.

I guess the error is on the line with the pair. Have you included the right header:

#include <utility>

Also, if you don't have using namespace std; or usgin std::pair;, you need to write std::pair, instead of just pair.

P.S. Please, don't use using namespace std;, especially header files.

EDIT Looking at your edit, you need #include <vector>, too.
EDIT2: You haven't defined NodeId, but you have used it for the typedef

edited Oct 08 '12 at 19:34

answered Oct 08 '12 at 19:22

Kiril Kirov

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>>Please, don't use using namespace std;, especially header files - why? – YAKOVM Oct 08 '12 at 19:28
Because any file that includes that header is going to be `using std` - cluttering the namespace. – Ivan Vergiliev Oct 08 '12 at 19:29
@Yakov - see http://stackoverflow.com/questions/1452721/why-is-using-namespace-std-considered-a-bad-practice-in-c – Kiril Kirov Oct 08 '12 at 19:30
is included - i justs did`t copy it – YAKOVM Oct 08 '12 at 19:32
@Yakov - see my edit: you haven't defined `NodeId` and you still haven't included the `utility` header. – Kiril Kirov Oct 08 '12 at 19:35

score 1 · Answer 2 · answered Oct 08 '12 at 19:32

It's a misleading error message. Neither iterator, nor NodeId are defined, and so can't be used in expressions.

You could work with this (making iterator a reference to a forward declared class): pair<iterator&,bool> insert(const Data nodeId);

and add a forward declaration for NodeId: class NodeId;

then do: typedef vector<NodeId&> DepList;

typedef inside class

2 Answers2