Explain simple code

#include <iostream>
#include <fstream>
#include <string>
using namespace std;
struct CarOwner {
string carBrand;
string lastName;
string firstName;
string middleName;
string phoneNumber;
string homeAddress;
string carNumber;
string techPassportNumber;
};
int main() {
ifstream input("input.txt");
ofstream output("output.txt");
if (!input.is_open()) {
cerr << "Ошибочка: не могу файл открыть" << endl;
return 1;
}
if (!output.is_open()) {
cerr << "Ошибочка: не могу файл открыть" << endl;
return 1;
}
CarOwner owner;
while (input >> owner.carBrand >> owner.lastName >> owner.firstName
>> owner.middleName >> owner.phoneNumber >> owner.homeAddress
>> owner.carNumber >> owner.techPassportNumber) {
if (owner.carBrand == "ВАЗ") {
output << owner.carBrand << " " << owner.lastName << " " << owner.firstName
<< " " << owner.middleName << " " << owner.phoneNumber << " "
<< owner.homeAddress << " " << owner.carNumber << " "
<< owner.techPassportNumber << endl;
}
}
input.close();
output.close();
return 0;
}

C

#include <iostream>

#include <fstream>

#include <string>

using namespace std;

struct CarOwner {

    string carBrand;

    string lastName;

    string firstName;

    string middleName;

    string phoneNumber;

    string homeAddress;

    string carNumber;

    string techPassportNumber;

};

int main() {

    ifstream input("input.txt");

    ofstream output("output.txt");

    if (!input.is_open()) {

        cerr << "Ошибочка: не могу файл открыть" << endl;

        return 1;

    }

    if (!output.is_open()) {

        cerr << "Ошибочка: не могу файл открыть" << endl;

        return 1;

    }

    CarOwner owner;

    while (input >> owner.carBrand >> owner.lastName >> owner.firstName

           >> owner.middleName >> owner.phoneNumber >> owner.homeAddress

           >> owner.carNumber >> owner.techPassportNumber) {

        if (owner.carBrand == "ВАЗ") {

            output << owner.carBrand << " " << owner.lastName << " " << owner.firstName

                   << " " << owner.middleName << " " << owner.phoneNumber << " "

                   << owner.homeAddress << " " << owner.carNumber << " "

                   << owner.techPassportNumber << endl;

        }

    }

    input.close();

    output.close();

    return 0;

}