#include <iostream>
#include <charconv>
#include <string>

int main()
{
	std::string str = "ff01aa00";
	
	for (std::size_t i = 0; i < str.size(); i += 2)
	{
		int val = -256;
		std::from_chars(&str[i], &str[i+2], val, 16);
		std::cout << val << " ";
	}
}