#include <fstream>
#include <iostream>
#include <string>
#include <vector>

int main()
{
	std::ifstream ifs("data.txt");
	if(!ifs.is_open())
	{
		std::cerr << "Missing data.txt." << std::endl;
		return -1;
	}

	for(std::string line; std::getline(ifs, line); )
	{
		if(line == "")
			continue;

		std::vector<char> buf;

		int idx = 0;
		for(const char &ch : line)
		{
			++idx;

			// clear out from beginning up until this character is found:
			auto i = std::find(buf.begin(), buf.end(), ch);
			if(i != buf.end())
				buf.erase(buf.begin(), i+1);

			buf.push_back(ch);

			if(buf.size() == 4)
			{
				std::cout << "Start-of-Packet at index " << idx << ": ";
				for(const char &ch : buf)
					std::cout << ch;
				std::cout << std::endl;
			}
			else if(buf.size() == 14)
			{
				std::cout << "Start-of-Message at index " << idx << ": ";
				for(const char &ch : buf)
					std::cout << ch;
				std::cout << std::endl;
			}
		}
	}

	return 0;
}