How to create a manager class for other classes.[Urgent]

[zealkaiser]

Hello! guys
I want to make class which can be used to create a collection of other classes.
For example I have a class Image, now i want to make a class which can be used to store multiple images. I have made the following Manager class

template <class t>
class Manager
{
std::vector<t> items;
int count;
public:
Manager();
~Manager();
int Add(t &item);
t *GetItem(int index);
};

template <class t>
Manager<t>::Manager()
{
items.clear();
count = -1;
}

template <class t>
Manager<t>::~Manager()
{
items.clear();
}

template <class t>
int Manager<t>::Add(t &item)
{
items.push_back(item);
count++;
return count;
}

template <class t>
t *Manager<t>::GetItem(int index)
{
return &items[index];
}

Now when i used
Manager<Image> images;
It gave me following error
build/Release/MinGW-Windows/GFX.o:GFX.cpp:(.text+0xe): undefined reference to `Manager<Image>::~Manager()'
build/Release/MinGW-Windows/GFX.o:GFX.cpp:(.text+0x291): undefined reference to `Manager<Image>::GetItem(int)'
build/Release/MinGW-Windows/GFX.o:GFX.cpp:(.text+0xe4d): undefined reference to `Manager<Image>::Add(Image&)'
build/Release/MinGW-Windows/GFX.o:GFX.cpp:(.text+0xf66): undefined reference to `Manager<Image>::Manager()'

[Mathhead200]

Are your method definitions in the same file as your class/method declarations?
Read the bottom section "Templates and multiple-file projects": http://cplusplus.com/doc/tutorial/templates

[Galik]

zealkaiser wrote:

I want to make class which can be used to create a collection of other classes.
For example I have a class Image, now i want to make a class which can be used to store multiple images.

To be honest those two don't sound like the same thing. Your 'manager class' sounds like a Factory Class which creates objects of different types (classes), but your example is actually a Container. That's not the really same thing.


EDIT:

Actually I think I now understand what you are saying. It is the collection that you want to create. So ignore my comment :)

[Computergeek01]

Mathhead200 is right, these are linking errors. Method definitions should be in a seperate .cpp file or the same header file as the declarations, but never in a different header file.