#include <iostream>
#include <string>
#include <math.h>

double stringToDouble(const std::string &str)
{
	double result = 0.0;
	bool isCommaExist = false;
	unsigned counter = 1;
	for (int i = 0; i < str.length(); i++)
	{
		if (str[i] == ',' || str[i] == '.') {
			isCommaExist = true;
			continue;
		}

		if (!isCommaExist) {
			result = result * 10 + (str[i] - '0');
		}
		else {
			result = result + double(str[i] - '0') / std::powl(10, counter);
			counter++;
		}
	}

	return result;
}

int main(int argc, char *argv[])
{ 
	std::string str;
	std::cout << "Vvedite chislo: ";
	std::cin >> str;
	std::cout << std::endl;
	
	std::cout << "Double: " << stringToDouble(str) << std::endl;

	system("PAUSE");
	
	return 0;
}