STL in MFC-based Application -- help pls!!!

I include
#include <vector>
using namespace std;
and declare the following in CMyApp class header file
std::vector<int> a(3);
but the compiler gave me error C2059: syntax error : 'constant' !!!
I do not know if there are any special setting in the compiler (I am using VC++6.0+SP5).
Any idea will be highly appreciated, Thank you.

Here is one way ...

• change in header file:
  
  Code:

  ---

  std::vector<int> a;

  ---

• in the CMyApp constructor :
  
  
  Code:

  ---

  a.resize(3);

  ---