abstract classes with generics in c++ / Qt - c++

Question

When I run the following code and press the enter button, I get a Segmentation Fault.
I've searched everywhere on the internet, but I can't find the problem. I'm quite new to C++/Qt.
The base class:
stack.h
#ifndef STACK_H
#define STACK_H
template <class T> class stack
{
public:
stack();
virtual T pop() = 0;
virtual void push(T i) = 0;
};
#endif // STACK_H
stack.cpp
#include "stack.h"
template<class T> stack<T>::stack()
{
}
arraystack.h
#ifndef ARRAYSTACK_H
#define ARRAYSTACK_H
#include "stack.h"
template <class T> class arraystack : public stack<T>
{
public:
arraystack();
T pop();
void push(T i);
};
#endif // ARRAYSTACK_H
arraystack.cpp
#include "arraystack.h"
#include <QDebug>
template<class T> arraystack<T>::arraystack()
{
}
template<class T> T arraystack<T>::pop(){
qDebug() << "popping bad";
}
template<class T> void arraystack<T>::push(T i){
qDebug() << "pushing shit";
}
The part that calls the pop-Function:
calculator.h
// ...
private:
Ui::calculator *ui;
arraystack<int> *h;
bool integer;
// ...
calculator.cpp
// ...
void calculator::on_b_enter_clicked()
{
h->pop();
}
// ...
Error:
The inferior stopped because it received a signal from the Operating System
Signal name: SIGSEGV
Signal meaning: Segmentation Fault

Answer 1

This code:
A.h
template <typename T>
class A
{
public:
A(){}
virtual void f1() = 0;
};
template <typename T>
class B: public A<T>
{
public:
B(){}
void f1(){}
};
main.cpp
#include "A.h"
int main ()
{
A<int> *a = new B<int>();
a->f1();
}
Compiles and works, because all template functions are defined in header file. If you want to split the declaration and the definition, you can use one of these methods:
Include the cpp file at the bottom of your header file
Include the cpp file in main.cpp