Unhandled exception at 0x5DF9CCC8 - c++

Question

when i run this code everything goes fine when writing , but when i press 2 to read it goes well and read everything just fine but when it it finishes reading the file (show function) it pops up a problem says " Unhandled exception at 0x5DF9CCC8 " with break , continue options .
from my searching i think the problem comes from a pointer points to Null , but i don't know how to resolve it .
here is the code
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");
}
}

Answer 1

Because you are using a string object instead of a plain character array, you can't just type cast the whole class to a char* and write it to the file (which in itself is a poor way of doing it. What if you changed around the order of the parameters and tried loading an older file?).
In your insert_data function, write each variable individually instead of casting the entire class. You could write the age and id first and you know that would take up 8 bytes, so whatever is remaining is the size of the name which can be loaded back into the string object in your read_data function.