#include <stdio.h>
#include <utility>
#include <numeric>
#include <string>
#include <iostream>
#include <vector>

int parse(const std::string& str) {
    if (str.empty()) {
        std::cout << "String is empty!";
        return 0;
    }
    if (str.size() > 20) {
        std::cout << "Value is to big to fit in integer!";
        return 0;
    }

    return std::stoi(str);
}

std::string read(const std::vector<int>& vec) {
    if (vec.empty()) {
        std::cout << "Vector is empty, can't read";
        return "";
    }
    if (vec.size() > 20) {
        std::cout << "Vector is to big";
        return "";
    }

    return std::accumulate(vec.begin(), vec.end(), std::string{}, [](const auto& str, int num){
        if (str.empty()) {
            return std::to_string(num);
        }
        return str + ", " + std::to_string(num);
    });
}

int main() {
    std::cout << "Parsed number: " << parse("-123") << '\n';
    std::cout << "Read numbers: " << read({1,2,3-1,-2,-3}) << '\n';
    std::cout << "Parsed number: " << parse("123456789012345678901234") << '\n';
    std::cout << "Read numbers: " << read({}) << '\n';
}