//	BigUn.cpp
//	Ed Smith
//	Dr. England
//	CS142, SP 2003
//	4/26/03
//	
//	interface for BigUn datatype:
//	designed to hold large unsigned values
//

#include	"BigUn.h"

// public toString Function
string BigUn::toString (void){
	return toString(bigNum);
}

// overloaded addition operator
string BigUn::operator+ (BigUn& other){
	unsigned a, b, tempLength, tempSum, carry = 0;
	SlistT<unsigned>  sumList;
	if ((getLength()) > (other.getLength()))
		tempLength = getLength();
	else
		tempLength = other.getLength();
	bigNum.reset();
	other.bigNum.reset();
	
	for (unsigned i = 0; i < tempLength; i++){
		if (!bigNum.get(a))
			a = 0;
		if (!other.bigNum.get(b))
			b = 0;
		cout << "a " << a << " b " << b << " carry " << carry << endl;
		tempSum = a + b + carry;
		carry = tempSum / 10;
		tempSum = tempSum % 10;
		sumList.insert(tempSum);
		sumList.move();
		bigNum.move();
		other.bigNum.move();
	}
	if (!(carry == 0))
		sumList.insert(carry);
	string s = toString(sumList);	
	return s;
}
		
//	overloaded assignment operator
//	assign other BigUn to BigUn
BigUn& BigUn::operator= (BigUn& other){
	string s = toString(other.bigNum);
	*this = s;
	return (*this);
}
//	overloaded assignment opperator
//	assign string of digits to BigUn
BigUn& BigUn::operator= (string strNum){
	unsigned temp;
	bigNum.clean();
	for (int i = 0; i < strNum.length(); i++){
		temp = strNum[i] - '0';
		bigNum.insert(temp);
	}
	return (*this);
}

//	overloaded multiplication operator
string BigUn::operator* (unsigned num){
	SlistT<unsigned> multList;
	unsigned a, tempMult, carry = 0;
	bigNum.reset();
	for (unsigned i = 0; i < getLength(); i++){	
		bigNum.get(a);
		tempMult = (a * num) + carry;
		carry = tempMult / 10;
		tempMult = tempMult % 10;
		cout << "a " << a << " num " << num << " carry " << carry << " tempMult "
			<<  tempMult << endl;
		multList.insert(tempMult);
		multList.move();
		bigNum.move();
	}
	while (!(carry == 0)){
		multList.insert(carry % 10);
		carry = carry / 10;
	}
	string s = toString(multList);
	return (s);
}
// accessors
unsigned BigUn::getLength (void) const{
	return (bigNum.length());
}

// print function
void BigUn::print(void){
	cout << toString (bigNum);
}

// convert the bigNum slist to a string
string BigUn::toString (SlistT<unsigned>& list){
	unsigned digit;
	string s;
	list.reset();
	while (list.get(digit)){
		s = (char) (digit + '0') + s;
		list.move();
	}
	return s;
}