Undefined Behavior fstream

#include <iostream>
#include <fstream>
 
using namespace std;
 
 
class Car
{
    string _nameOfCarCompany;
    int _airbagsNumber;
 
public:
 
    Car(){};
    Car(string name, int number): _nameOfCarCompany(name), _airbagsNumber(number){}
 
    string getNameOfCarCompany()
    {
        return _nameOfCarCompany;
    }
 
    int getAirbagsNumber()
    {
        return _airbagsNumber;
    }
 
    void setNameOfCarCompany(string name)
    {
        _nameOfCarCompany = name;
    }
 
    void setAirbagsNumber(int number)
    {
        _airbagsNumber = number;
    }
 
};
 
int main()
{
    Car *cars[3];
    int i;
    string name = "";
    int number;
    for(i = 0; i < 3; ++i)
    {
        cout << "Enter the name of car company: ";
        cin >> name;
        cout << "Enter the number of airbags: ";
        cin >> number;
        cars[i] = new Car(name, number);
    }
    fstream fs;
    string buf = "";
    int numBuf;
    fs.open("cars.txt", fstream::out | fstream::in | fstream::app);
    if(fs.is_open())
    {
        i = 0;
        while(!fs.eof())
        {
            buf = cars[i]->getNameOfCarCompany();
            fs << buf << "\n";
            numBuf = cars[i]->getAirbagsNumber();
            fs << numBuf << "\n";
            i++;
        }
    }
    else
        cout << "File haven't been opened:(" << endl;
    fs.close();
    string carToFind = "";
    cout << "Enter the name of car company you want to find: ";
    cin >> carToFind;
    fs.open("cars.txt", fstream::in | fstream::out | fstream::app);
    if(fs.is_open())
    {
        i = 0;
        while(!fs.eof())
        {
            buf = "";
            numBuf = 0;
            fs >> buf;
            cars[i]->setNameOfCarCompany(buf);
            fs >> numBuf;
            cars[i]->setAirbagsNumber(numBuf);
            i++;
        }
    }
    else
        cout << "File haven't been opened:(" << endl;
    fs.close();
    for(i = 0; i < 3; ++i)
    {
        if(cars[i]->getNameOfCarCompany() == carToFind)
        {
            cout << "Car you was looking for: " << endl;
            cout << "Name of car company: " << cars[i]->getNameOfCarCompany() << endl;
            cout << "Number of airbags: " << cars[i]->getAirbagsNumber() << endl;
        }
    }
    return 0;
}