Hello
I am working on a text-based rpg, using C++ and I have some trouble with std::vectors. I've created a vector in my namespace called "Initialize" , in its header. In "Initialize.cpp" I add objects of the type "Items" to the vector using push_back.

I want to know how I can access the objects in my vector I've created in my namespace "Initialize" from my Item-class.

Example:

GetItemName(Diablo::Initialize::existingItems[1]) //GetItemName returns the name of the object it receives.
                                                  // This doesn't work since I have to include "Initialize.h"
                                                  // which gives linker-errors.

The problem is that if I include "Initialize.h" to be able to access the vector defined in "Initialize.h", i'll get linker-errors since the the vector will be defined both in my "Initialize.h" and in my "Items.cpp".

How can I declare my vector so that I can easily access from other classes etc.?

You cannot just declare any variable in a header file (whether this is a simple int or an std::vector).

You need an extern declaration in the header

// MyFile.h
extern std::vector<MyType> myVariable;

and then the actual declaration in exactly one compilation unit:

// MyFile.cpp
std::vector<MyType> myVariable;

Edit: For the future I would also advise posting the exact errors you getting. It's pretty clear what the problem is now, but in the general case the exact errors are essential.