Unresolved external symbol error

Question

I created an external class of a stack and when i try to use it it says unresolved external symbol.
I declared and implemented the functions in the header and cpp file but i can't see the problem. What may cause it? Important:

its a template class and all functions got template <class T>...

Instantiation: Stack<int> st;
St.push(1);...// the problem starts here

Ternary ... Void stack<T> ::Push(T val)
{
arr[place] = val;
place++;
}

Answer 1

If it is an LNK2019 error, then here is a bullet list of possible sources of the issue.

https://msdn.microsoft.com/en-us/library/799kze2z.aspx