Как мне корректно записать на файл, и считать с файла информацию

   struct bank 
{
    client* arr;
    unsigned int number_of_client = 0;
    string name;
    unsigned int annual_percentage;
};

struct country
{
    string name;
    unsigned int number_of_banks = 0;
    bank* arr;
};


struct client
{
    string name;
    unsigned int sum_contribution;
    string address;
};

 void keepFile(fstream& file,country*& arr,int number_of_country) {
        file.close();
        file.open("information.txt", ios::out | ios::in);
        for (int i = 0; i < number_of_country; i++)
        {
            file.write((char*)&arr[i], sizeof(arr[i]));
        }
    }

    void giveInformation(fstream& file, country*& arr, int number_of_country) {
        for (int i = 0; i < number_of_country; i++) {
            country buffer;
            file.read((char*)&buffer, sizeof(arr[i]));
            cout << "Страна " << buffer.name << endl << "количество банков в стране" << buffer.number_of_banks << endl;
            for (int j = 0; j < arr[i].number_of_banks; j++)
            {
                cout << "Банк " << buffer.arr[j].name << endl;
                for (int n = 0; n < buffer.arr[j].number_of_client; n++)
                {
                    cout << buffer.arr[j].arr[n].name << " " << buffer.arr[j].arr[n].address << buffer.arr[j].arr[n].sum_contribution;
                }
            }
        }

    }