readlines

gistfile1.cpp

#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include <array>

int
main()
{
	std::ifstream ifs("/etc/passwd");
	std::string line;
	while (std::getline(ifs, line))
	{
		std::stringstream ss(line);
		std::array<std::string, 3> tokens;
		for (auto & el : tokens)
		{
			std::getline(ss, el, ':');
		}
		if (!tokens[2].empty() && std::stoi(tokens[2]) > 500)
		{
			std::cout << tokens[0] << "/uid " << tokens[2] << std::endl;
		}
	}
}