0x5DF9CCC8处出现未处理的异常

当我运行此代码时，写入时一切都很顺利，但当我按2读取时，一切都很好，但当它完成读取文件（显示函数）时，会弹出一个问题，显示"0x5DF9CCC8处未处理的异常"，并带有break，continue选项。从我的搜索中，我认为问题来自一个指向Null的指针，但我不知道如何解决它。这是代码

class person{
public :
string name;
int id ;
int age ;
void person :: show();
void person :: add_menue();
void person :: insert_data();
void person :: show_data();
};
person personobject;
  void person :: add_menue()
{
    cout << "Please Enter Name ID Age :" << endl;
    cin >> name >> id >> age ;
}
ofstream file;
void person::show()
{
    cout<<"Age  => "<<age<<endl;
    cout<<"Name => "<<name<<endl;
    cout<<"ID   => "<<id<<endl;
}
void person :: insert_data()
{
    ofstream file;
    file.open("binary.dat",ios::app| ios::binary);
    personobject.add_menue();
    file.write((char*)&personobject, sizeof(personobject));
    file.close();
}
void person :: show_data()
{
    ifstream file;
    file.open("binary.dat",ios::in| ios::binary);
    if(!file)
    {
        cout<<"File not Found";
    }
    else
    {
        file.read((char*)&personobject, sizeof(personobject));
        while(!file.eof())
        {
            personobject.show();
            cout<<"Press Any Key....For Next Record"<<endl;
            getchar();
            file.read((char*)&personobject, sizeof(personobject));
            }
    }
    file.close();
}
void main ()
{
    int choice;
    cout << "1 - to write n2 - to  read" << endl;
    cin >> choice;
    if (choice==1)
    {
        person f;
        f.insert_data();
    }
    if (choice==2)
    {
        person a;
        a.show_data();
        system ("pause");
    }
}