[C++]Error Frage

#include "stdafx.h"
#include "Funktionen.h"
#include <string>
#include <iostream>
#include <algorithm>
#include <vector>
#include <boost\algorithm\string.hpp>

int main()
{
	Funktionen f;
	

	while (true)
	{
		std::vector<std::string> results;
		std::string s;
		std::cin >> s;

		if(s.find('+'))
		{
			boost::split(results, s, boost::is_any_of("+"), boost::token_compress_on);
			std::cout << f.Addieren(atoi(results[0].c_str()), atoi(results[1].c_str())) << std::endl;
		}
		if (s.find('*'))
		{
			boost::split(results, s, boost::is_any_of("*"), boost::token_compress_on);
			std::cout << results.capacity();
			std::cout << f.Multiplizieren(atoi(results[0].c_str()), atoi(results[1].c_str())) << std::endl;
		}
	}
	return 0;
}

#include <iostream>
#include <string>
#include <cctype>

template <typename iterator>
int expression (iterator & begin, iterator end);
template <typename iterator>
int term (iterator & begin, iterator end);
template <typename iterator>
int factor (iterator & begin, iterator end);
template <typename iterator>
int number (iterator & begin, iterator end);

int main () {
	std::cout << "expression: ";
	std::string input;
	getline (std::cin, input);
	try {
		auto begin = input.begin ();
		auto end = input.end ();
		int value = expression (begin, end);
		std::cout << "value: " << value;
		if (begin != end)
			std::cout << "\ninput not completely parsed";
	} catch (const char * exception) {
		std::cout << "error: " << exception;
	}
	std::cout << '\n';

	std::cin.get ();
}

template <typename iterator>
int expression (iterator & begin, iterator end) {
	int sum = term (begin, end);
	while (begin != end)
		if (* begin == '+')
			sum += term (++begin, end);
		else if (* begin == '-')
			sum -= term (++begin, end);
		else
			return sum;
	return sum;
}

template <typename iterator>
int term (iterator & begin, iterator end) {
	int product = factor (begin, end);
	while (begin != end)
		if (* begin == '*')
			product *= factor (++begin, end);
		else if (* begin == '/') {
			int denominator = factor (++begin, end);
			if (! denominator)
				throw "division by zero";
			product /= denominator;
		} else
			return product;
	return product;
}

template <typename iterator>
int factor (iterator & begin, iterator end) {
	if (begin == end)
		throw "unexpected end of input";
	if (* begin == '(') {
		int value_inside = expression (++begin, end);
		if (begin == end || * begin != ')')
			throw "missing ')'";
		++begin;
		return value_inside;
	}
	return number (begin, end);
}

template <typename iterator>
int number (iterator & begin, iterator end) {
	int value = 0;
	if (begin == end || ! std::isdigit (* begin))
		throw "expected a number";
	do {
		value *= 10;
		value += * begin - '0';
		++begin;
	} while (begin != end && std::isdigit (* begin));
	return value;
}