serialize

#include <iostream>
#include <string>
#include <cstring>
#include <sstream>

void write_string(std::stringstream & ss, std::string const & s) {
    auto len = s.size();
    ss.write(reinterpret_cast<const char *>(&len), sizeof(len));
    ss.write(s.c_str(), len);
}

void read_string(std::stringstream & ss, std::string & s) {
    auto len = s.size();
    ss.read(reinterpret_cast<char *>(&len), sizeof(len));
    s.resize(len);
    ss.read(&s[0], len);
}

struct User
{
    std::string name;
    std::string address;
    int age;

    void serialize(std::stringstream & ss) const {
        ss.write(reinterpret_cast<const char *>(&age), sizeof(int));
        write_string(ss, name);
        write_string(ss, address);
    }

    void deserialize(std::stringstream & ss) {
        ss.read(reinterpret_cast<char *>(&age), sizeof(int));
        read_string(ss, name);
        read_string(ss, address);
    }
};

int main() {
    User usrName;
    User usrName2;

    usrName.address="viseu";
    usrName.age=23;
    usrName.name="joaquim";

    std::stringstream ss;
    usrName.serialize(ss);

    for(auto && c : ss.str()) {
        std::cout<< std::hex << static_cast<unsigned int>(c) << ' ';
    }
    std::endl(std::cout);

    ss.seekg(0);
    usrName2.deserialize(ss);

    std::cout<< usrName2.name << std::endl
        << usrName2.address << std::endl
        << std::dec << usrName2.age << std::endl;
    return 0;
}