How to fix pointer being freed was not allocated c++

My program works fine hours ago and suddenly doesn't work anymore, Iam really sorry to post all codes but I am totally confused with what went wrong there.

#include <iostream>
#include <fstream>

using namespace std;

class Car
{
protected:
    string carmodel;
    string serialnumber;
    string description;
    int    yearmade;

public:
    Car ()
    {
    }
};

class Service
{
protected:
    string serviceinfo;
    int lmonth, nmonth,lday, nday, lyear, nyear, mbetw;

public:
    Service ()
    {
    }

    void udate(void)
    {
        nday = lday;
        nmonth = lmonth;//is this necessary
        nyear = lyear;
        nmonth = lmonth + mbetw;
        while (nmonth > 12)
        {
            nyear  = nyear  + 1;
            nmonth = nmonth - 12;
        }

    }

};

class Autobody: public Car, public Service
{
public:
    Autobody()
    {
    }
    static void file_write(int n);
    static void serial_file_read(string serial);
    static void date_file_read(int d, int m, int y);
    friend istream &operator >> (istream &in , Autobody &iinfo);
    friend ostream &operator << (ostream &out , Autobody &oinfo); 
};

void Autobody:: file_write(int n)
{
    Autobody *a1 = new Autobody[n];
    for (int i = 0; i < n; i++)
    {
        cin >> a1[i];
        a1[i].udate();
    }
    ofstream fdata("cars.txt", ios::app);
    fdata.seekp(0, ios::end);
    fdata.write((char*) a1, n*sizeof(Autobody));
    fdata.close();
    delete []a1;
}

void Autobody:: date_file_read(int d, int m, int y)
{
    int n;
    ifstream fdata2("cars.txt", ios::in);
    if (!fdata2)
    {cout << "Nothing in the file,please run again and create a file first"<<endl;
         exit(1);
    }
    fdata2.seekg(0,ios::end);
    n = fdata2.tellg() / sizeof(Autobody);
    Autobody *a2 = new Autobody[n];
    fdata2.seekg(0,ios::beg);
    fdata2.read((char*) a2 , n*sizeof(Autobody));

    for (int i = 0 ; i < n ; i++)
    {
        if ((d == a2[i].nday) & (m == a2[i].nmonth) & (y == a2[i].nyear))
            cout << a2[i];
    }
    fdata2.close();
    delete []a2;
}

void Autobody::serial_file_read(string serial)
{
    int d;
    ifstream filed2("cars.txt", ios::in);
    if (!filed2)
    {cout << "Nothing in the file,please run again and create a file first"<<endl;
        exit(1);
    }
    filed2.seekg(0,ios::end);
    d = filed2.tellg() / sizeof(Autobody);
    Autobody *a2 = new Autobody[d];
    filed2.seekg(0,ios::beg);
    filed2.read((char*) a2 , d*sizeof(Autobody));
    for (int i = 0 ; i < d ; i++)
    {
        if (strcmp(serial.c_str(),a2[i].serialnumber.c_str()) ==0)
            cout << a2[i];
    }
    filed2.close();
    delete []a2;
}

istream &operator >> (istream &in , Autobody &info)
{
    cout << " Input car model: ";
    in.ignore();
    getline(cin,info.carmodel);
    cout << " Input licence plate number: ";
    in >> info.serialnumber;
    cout << " Input year made: ";
    in >> info.yearmade;
    cout << " Input car description: ";
    in.ignore();
    getline(cin, info.description);
    cout << " Input service start date(Day month year): " ;
    in >> info.lday >> info.lmonth >> info.lyear ;
    cout << " Input months between two service: ";
    in >> info.mbetw;
    cout << " Input service information: ";
    in.ignore();
    getline(cin, info.serviceinfo);
    cout << " Info is appended"<<endl;
    return in;
}

ostream &operator << (ostream &out , Autobody &info)
{
    out << "Car model: "<<info.carmodel<<endl;
    out << "Serial number: " << info.serialnumber << endl;
    out << "Car description: " << info.description << endl;
    out << "Service information: " << info.serviceinfo << endl;
    out << "Last service date and next service date(day month year): " << info.lday << "/" << info.lmonth << "/" << info.lyear<<"-"<<info.nday << "/" << info.nmonth << "/" << info.nyear <<endl;
    return out;
}

void displaymenu(){
    cout<<endl;
    cout<< "1.Create new car record"<<endl;
    cout<< "2.Search by serial number"<<endl;
    cout<< "3.Search by next service date"<<endl;
    cout<< "0.Exit"<<endl;
    cout<<endl;
}
int main ()
{
    int option;
    int day, month, year;
    string serialnumber;
    cout<<"This is the car managing system,select your function press 0-3"<<endl;
    while(true)
    {
        displaymenu();
        cout << "Choose the option: ";
        cin >> option;
        cout <<endl;
        switch(option){
            case 1:
                Autobody::file_write(1);
                break;

            case 2:
                cout << "Enter serial number: ";
                cin >> serialnumber;
                cout <<endl;
                Autobody::serial_file_read(serialnumber);
                break;

            case 3:
                cout << "Enter the date(day month year): ";
                cin >> day >> month >> year;
                cout << endl;
                Autobody::date_file_read(day,month,year);
                break;

            case 0:
                cout << "Thanks for using!" << endl;
                break;

            default:
                cout << "You have to choose between 0 - 3 \t"<<endl;
                break;
        }
    };
    return 0;
}

The error shows: project_test_again(1945,0x1000e2d40) malloc: * error for object 0x10000000c: pointer being freed was not allocated project_test_again(1945,0x1000e2d40) malloc: * set a breakpoint in malloc_error_break to debug