Implementing a stack using a linked list and class templates - c++

Question

I'm trying to implement a stack using a linked list and class template. I'm not getting any compiler errors but my logic may be wrong, kind of lost. I had a working program in just a single file only using a struct so I had difficulties with translating it over using multiple files and template classes. I will also include my single file cpp below, hopefully it helps. Any help will be greatly appreciated. I have a header.h file, functions.cpp and main. cpp.
Header.h
#define STACK_H
#include <iostream>
using namespace std;
//to implement a stack using linked list
template<class T>
class node{
public:
T data;
node<T>*next;
};
template<class T>
class stack{
private:
node<T> *item;
node<T> *top;
public:
stack(); // constructor
void push( node<T> *); // to insert an item to the stack
void pop(); // to remove an item from the stack
void display(); // to display the stack elements on screen
node<T> *newnode(int );
};
#include "functions.cpp"
#endif
functions.cpp
#include <iostream>
#include "header.h"
#ifndef FUNCTIONS
#define FUNCTIONS
using namespace std;
template<class T>
stack <T> :: stack(){
node<T> *top = NULL;
}
template<class T>
void stack <T> :: push(node<T> * q){
if (top == NULL)
top = q;
else
{
q->next = top;
top = q;
}
}
template<class T>
void stack <T> :: pop(){
if (top == NULL) {
cout << "Stack is empty";
}
else {
cout << "Popped element is " << top->data;
item = top;
top = top->next;
delete(item);
}
}
template<class T>
void stack <T> :: display(){
node<T> *q;
q = top;
if (top == NULL) {
cout << "Stack is empty!!";
}
else {
while (q != NULL)
{
cout << q->data << " ";
q = q->next;
}
}
}
template<class T>
node<T> * stack <T> :: newnode(int x)
{
item = new node<T>;
item->data = x;
item->next = NULL;
return(item);
}
#endif
main.cpp
#include<iostream>
#include "header.h"
using namespace std;
int main()
{
int ch, x;
stack <int> myStack;
node<int> *nptr;
do
{
cout << "\n\n1.Push\n2.Pop\n3.Print Stack\n4.Exit";
cout << "\nPlease enter a function(1-4):";
cin >> ch;
if (ch == 1)
{
cout << "\nEnter data:";
cin >> x;
nptr = myStack.newnode(x);
myStack.push( nptr);
}
else if (ch == 2)
{
myStack.pop();
}
else if (ch == 3)
{
myStack.display();
}
else cout << "\nInvalid Entry";
} while (ch != 4);
return 0;
}
Single file working program
struct nodeType
{
int data;
nodeType *next;
};
nodeType *top = NULL;
nodeType *p;
nodeType* newnode(int x)
{
p = new nodeType;
p->data = x;
p->next = NULL;
return(p);
}
void push(nodeType *q)
{
if (top == NULL)
top = q;
else
{
q->next = top;
top = q;
}
}
void pop() {
if (top == NULL) {
cout << "Stack is empty";
}
else {
cout << "Popped element is " << top->data;
p = top;
top = top->next;
delete(p);
}
}
void printStack()
{
nodeType *q;
q = top;
if (top == NULL) {
cout << "Stack is empty!!";
}
else {
while (q != NULL)
{
cout << q->data << " ";
q = q->next;
}
}
}
int main()
{
int ch, x;
nodeType *nptr;
do
{
cout << "\n\n1.Push\n2.Pop\n3.Print Stack\n4.Exit";
cout << "\nPlease enter a function(1-4):";
cin >> ch;
if (ch == 1)
{
cout << "\nEnter data:";
cin >> x;
nptr = newnode(x);
push(nptr);
}
else if (ch == 2)
{
pop();
}
else if (ch == 3)
{
printStack();
}
else cout << "\nInvalid Entry";
} while (ch != 4);
return 0;
}