Deque template class

[Hiten]

So I'm trying to make my version of a deck class which has several members like addFirst, addLast, removeFirst, etc... I also want it to be iterable.
So with returnFirst function I'm trying to return the first node of deck but i get several errors:

1>e:\home\deque\deque\deque.h(10): 
warning C4346: 
'Deque<T>::Node' : dependent name is not a type
1>          prefix with 'typename' to indicate a type
1>          e:\home\deque\deque\deque.h(32) :
 see reference to class template instantiation 'Deque<T>' being compiled
1>e:\home\deque\deque\deque.h(10):
error C2143: syntax error : missing ';' before '*'
1>e:\home\deque\deque\deque.h(10): 
error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
1>e:\home\deque\deque\deque.h(10): 
fatal error C1903: unable to recover from previous error(s); stopping compilation

This is my header file:

Deque.h
template<class T>
class Deque{
public:
	Deque();
	~Deque();
	void addFirst(T item);
	void addLast(T item);
	void removeFirst();
	void removeLast();
	Deque<T>::Node * Deque<T>::returnFirst(){
		(first == nullptr) ? throw "Null Pointer Exception: first element" : return first;
	}  //not sure if it's correct
	friend void displayDeque(Deque<T> &deck);
	bool isEmpty() const{
		return (count == 0);
	}

	int size() const{
		return count;
	}

private:
	struct Node{
		T data;
		struct Node *next;
		struct Node *previous;
	};

	Node *first;
	Node *last;
	int count;
};

template<class T>
Deque<T>::Deque():first=nullptr, last = nullptr, count = 0{
}

template<class T>
Deque<T>::~Deque(){

}

template<class T>
void Deque<T>::addFirst(T item){
	if(isEmpty()){
		first->data = last->data = item;
		first->previous = first->next = last->previous= last->next = nullptr;
	}
	else{
		Node<T> * newNode = new Node;
		newNode->data = item;
		first->previous = newNode;
		newNode->next = first;
		newNode->previous = nullptr;
		first = newNode;
	}
}

template<class T>
void displayDeque(Deque<T> deque){
	Node<T> *current = first;
	if(isEmpty)
		cout << "Deck is empty" << endl;
}

and main

#include "Deque.h"
#include <iostream>
#include <string>
using namespace std;

int main(){
	Deque<int> *deck = new Deque<int>();
}

Many thanks to anyone willing to help out a noob :)

[ne555]

'Deque<T>::Node' : dependent name is not a type
1> prefix with 'typename' to indicate a type

typename Deque<T>::Node * Deque<T>::returnFirst(){


Also

Deque<int> *deck = new Deque<int>();
Deque<int> deck;

[Hiten]

Thanks ne555, I've made the changes you suggested and I get :

1>          e:\home\deque\deque\deque.h(32) :
 see reference to class template instantiation 'Deque<T>' being compiled
1>e:\home\deque\deque\deque.h(20):
 error C2334: unexpected token(s) preceding '{'; skipping apparent function body

[ne555]

template<class T>
class Deque{
private:
	struct Node; //forward declaration (for returnFirst() )
public:
	Deque();
	~Deque();
	void addFirst(T item);
	void addLast(T item);
	void removeFirst();
	void removeLast();
	Node* returnFirst(){ //simple
		if(first == nullptr) //you were abusing the ?: operator
			throw "Null Pointer Exception: first element";
		return first;
	}
	void displayDeque() const; //a member function seems more adequate
	bool isEmpty() const{
		return (count == 0);
	}

	int size() const{
		return count;
	}

private:
	struct Node{
		T data;
		struct Node *next;
		struct Node *previous;
	};

	Node *first;
	Node *last;
	int count;
};

template<class T>
Deque<T>::Deque():first(nullptr), last(nullptr), count(0){
}

template<class T>
Deque<T>::~Deque(){

}

template<class T>
void Deque<T>::addFirst(T item){
	if(isEmpty()){
		first->data = last->data = item;
		first->previous = first->next = last->previous= last->next = nullptr;
	}
	else{
		Node *newNode = new Node; //Node is not a template
		newNode->data = item;
		first->previous = newNode;
		newNode->next = first;
		newNode->previous = nullptr;
		first = newNode;
	}
}

#include <iostream>

template<class T>
void Deque<T>::displayDeque() const{
	Node *current = first;
	if(isEmpty)
		std::cout << "Deck is empty" << std::endl;
}


#include <iostream>
#include <string>
using namespace std;

int main(){
	Deque<int> deck;
}

[Hiten]

Big thanks Nee. Basically returnFirst didn't know about the Node structure?

[ne555]

¿why did I bother to comment the changes?