// Programmieren 1, Praktikum 3, Aufgabe 5
// Sven Eisenhauer
// 17.11.2004
//
// file: main.cpp
//
// purpose: egypt multiplication          
//          
//
#include <iostream>
using std::cin;
using std::cout;
using std::endl;

int multIterative(int,int);
void multRecursive(int,int, int &);

int main()
{
	int number1,
		number2,
		erg;
	
	cout << "1st number: ";
	cin >> number1;
	cout << "2nd number: ";
	cin >> number2;

	cout << "Product: " << multIterative(number1,number2) << endl;
	multRecursive(number1,number2,erg);
	cout << "Product: " << erg << endl;

	return 0;
}

int multIterative(int a,int b)
{
	int product=0;
	while (b>0)
	{
		if (0 != b%2)
			product+=a;

		a = a << 1;
		b = b >> 1;
	}
	return product;
}

void multRecursive(int a,int b, int &product)
{
	int	x,y;

	if (b<=1)
		product=a;

	else
	{
		x=a<<1;
		y=b>>1;
		multRecursive(x,y,product);
		if (0!=b%2)
			product+=a;

	}
		
}