Как исправить return 1id?

#include <iostream>
using namespace std;
class lists{
	
	struct Element{ 
		int data;  
		Element * next; 
	};
	
	Element * firstElement; 
	Element * lastElement; 
	
	void AddElement(int n){
		Element * elm = new Element; 
		elm -> data = n; 													 
		cout << elm;																
		if(firstElement == NULL && firstElement != lastElement){				  
			firstElement = elm;
		}																				
																					
																						
		
													
		
		
	}
	
	int main(){
		int count; 
		int n = 5;
		AddElement(n);
		return 0;
	}
};