problem with multimap<T, int>::iterator class member

[Paul Rice]

I'm trying to add a multimap as a member of a template class and I'm having trouble declaring and iterator. It seems to work when I declare the multimap member but not the iterator.

#include <iostream>
#include <vector>
#include <map>
#include <iomanip>
using namespace std;

template <class T>
class Test{
    typedef multimap<T,int> MMap;

    public:
        MMap data;
        multimap<T,int>::iterator pos;
};


int main()
{
	std::cout << "Hello world!" << std::endl;
	return 0;
}

The error i get is "expected ';' before pos"

Is there a fix to this or am I asking too much?

Thanks

[MrViggy]

I think this will work:

template <class T>
class Test{
    typedef multimap<T,int> MMap;

    public:
        MMap data;
        typename  multimap<T,int>::iterator pos;
};

Viggy

[ltcmelo]

Hi.

In this case, the iterator type is dependent on the type of T. Therefore, you need to use keyword typename to tell the compiler about this dependency. When you define the type directly, as in the code bellow, you don't need to use typename.

template <class T>
class Test
{
  typedef std::multimap<T,int> MMap;

public:
  MMap data;

  //Here, you need typename.
  typename  std::multimap<T,int>::iterator dependent;

  //Here (no T), you don't need typename.
  std::multimap<int,int>::iterator nondepedent;
};