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

void transfer(char symbol, std::string first, std::string second) {
    std::ifstream file(first);
    std::ofstream output(second, std::ios::out | std::ios::trunc);

    if (!file.is_open() || !output.is_open()) return;

    std::string line;
    while (true) {
        int i = file.get();

        if (i <= 0) break;

        char c = (char)i;

        line += c;

        if (c == '\n') {
            if (std::find(line.begin(), line.end(), symbol) != line.end())
                output << line;
            line.clear();
        }
    }

    file.close();
    output.flush();
    output.close();
}

int main() {
    transfer('0', "hello.txt", "world.txt");
    return 0;
}