/****************************************************************
*  Engineering 4892 Data Structures
*  Assignment: 4 Question 2  Date Due: July 5th/2001
*  Name: Daryl Martin
*  Student #: 9713520
*  Username: darylm
*****************************************************************/

#include "BigNatR.h"



/*****************************************************************
* makeList - Create a linked list containing the digits in r 
*			 as your data
*
*	Post: Result = head of the list representing r
*****************************************************************/

Node* BigNat::makeList(unsigned long r) {

	int data = 0;		

	data = r % 10;	//pick the last digit off the value r
	r = r/10;	//drop the last digit off the value r
	
	
	Node* toAdd = new(std::nothrow) Node;	//create our new node
		
		if(toAdd != 0) {	//if there is memory than...	
			toAdd->digit = data;	//store the data in the node
			toAdd->next = makeList(r);	//recursive function call
			err = Ok;	
		}

		else {err = NewFail;} 
		
}


/*****************************************************************
* makeULong - Converts the list to an unsigned long integer
*
*	Post: err = Ok -> Result = D converted to an unsigned long 
*		  err = Overflow <-> D is too big for an unsigned long
*****************************************************************/

unsigned long BigNat::makeULong(const Node *l) const {
       unsigned long result = 0;
       
	   if(l != 0 && err != Overflow) {
       		   unsigned long add = makeULong(l->next);
               result = l->digit + 10*add;	
       
			   if(result < add){ err = Overflow;} //Given post condition
       }

       return result;
}