#include <iostream>

using namespace std;


class nodeClass {
  friend class linkedListClass;
public:

  nodeClass(int newvalue) {
    dvalue=newvalue;
    next = NULL;
	edgePtr = NULL;
	label = 'Z';
  }

private:
  int dvalue;
  nodeClass *next;
  union {
	nodeClass *edgePtr;
	char label;
  };

};

class linkedListClass {
public:
  linkedListClass() {
    first = NULL;
  }

  linkedListClass(int nodevalue) {
    first = new nodeClass(nodevalue);
  }

  void testUnion() {
	  cout << "edge: " << first->edgePtr << endl;
	  cout << "label: " << first->label << endl;

	  first->edgePtr = first->next;
	  cout << "edge: " << first->edgePtr << endl;
	  cout << "label: " << first->label << endl;

	  first->label = 'A';
	  cout << "edge: " << first->edgePtr << endl;
	  cout << "label: " << first->label << endl;

  }


  void addbehind(int newvalue) {
    nodeClass *newnode = new nodeClass(newvalue);

    if (first == NULL)
      first = newnode;
    else {
      newnode->next = first->next;
      first->next = newnode;
    }

  }

  void addinfront(int newvalue) {
    nodeClass *newnode = new nodeClass(newvalue);

    if (first == NULL)
      first = newnode;
    else {
      newnode->next = first;
      first = newnode;
    }
  }


  int getdvalue() {
    if (first == NULL)
      return -1;
    else
      return(first->dvalue);
  }

  void printlist() {
    nodeClass *currentNode;
    if (first == NULL)
      cout << "The List is currently empty.\n";
    else {
      currentNode = first;
      cout << "\nHere is the current list: \n";
      while (currentNode != NULL) {
		cout << "\tcurrent node is " 
			 << currentNode->dvalue 
			 << endl;
		currentNode = currentNode->next;
      }
    }

  }


private:

  nodeClass *first;
};

int main() {

  linkedListClass *myList;

  myList= new linkedListClass();

  myList->addbehind(23);


  cout << "From main: \n\tthe value is " << myList->getdvalue() << endl;

  myList->addbehind(45);
  myList->printlist();

  myList->addinfront(10);
  myList->printlist();

  myList->testUnion();
  return 0;
}