Edit specific string in text file in C++ - c++

Question

How to edit specific string in text file?
I use my logic but it's not working..
Really appreciate anyone help me
Here is my Add Function
void Admin::add_dvd()
{
string id, copy, title, genre, dir, rentdate, returndate, fee;
ofstream myfile("dvd_list.txt", ios::out | ios::app);
cin.get();
cout << "DVD ID: " << endl;
getline(cin, id);
cout << "Copy Number: " << endl;
getline(cin, copy);
cout << "Title: " << endl;
getline(cin, title);
cout << "Genre: " << endl;
getline(cin, genre);
cout << "Director: " << endl;
getline(cin, dir);
cout << "Rental Date: " << endl;
getline(cin, rentdate);
cout << "Return Date: " << endl;
getline(cin, returndate);
cout << "Rental Fee: " << endl;
getline(cin, fee);
myfile << endl << id << " | " << copy << " | " << title << " | " << genre << " | " << dir << " | " << rentdate << " | " << returndate << " | " << fee << endl;
myfile.close();
cout << "DVD Added." << endl;
system("pause");
}
This is the EDIT FUNCTION
void Admin::edit_dvd()
{
string id;
cout << "Enter DVD ID: " << endl;
cin >> id;
ifstream myfile("dvd_list.txt");
if (myfile.is_open())
{
while (!myfile.eof())
{
myfile >> dvd_id >> title >> genre >> dir >> rent_date >> return_date >> copy_num >> rent_fee;
if (id == dvd_id)
{
int choice;
cout << dvd_id << title << genre << dir << rent_date << return_date << copy_num << rent_fee << endl;
cout << "Which part you want to edit? " << endl;
cout << "1) DVD ID" << endl;
cout << "2) DVD Title" << endl;
cout << "3) Genre" << endl;
cout << "4) Director" << endl;
cout << "5) Rent Date" << endl;
cout << "6) Return Date" << endl;
cout << "7) Copy Number" << endl;
cout << "8) Rent Fee" << endl;
cout << "9) Cancel" << endl;
cout << "Enter number: " << endl;
cin >> choice;
switch (choice)
{
case 1:
{
string id;
cout << "Enter new DVD ID: " << endl;
cin >> id;
id = dvd_id;
}
case 2:
{
string ttl;
cout << "Enter new DVD Title: " << endl;
cin >> ttl;
ttl = title;
}
case 3:
{
string gen;
cout << "Enter new Genre: " << endl;
cin >> gen;
gen = genre;
}
case 4:
{
string director;
cout << "Enter new Director: " << endl;
cin >> director;
director = dir;
}
case 5:
{
string rdate;
cout << "Enter new Rent Date: " << endl;
cin >> rdate;
rdate = rent_date;
}
case 6:
{
string retdate;
cout << "Enter new Return Date: " << endl;
cin >> retdate;
retdate = return_date;
}
case 7:
{
string cnumber;
cout << "Enter new Copy Number: " << endl;
cin >> cnumber;
cnumber = copy_num;
}
case 8:
{
string rfee;
cout << "Enter new Rent Fee: " << endl;
cin >> rfee;
rfee = rent_fee;
}
case 9:
{ break; }
}
}
else
{
cout << "No data matched!" << endl;
break;
}
}
myfile.close();
}
}
And this is the Txt File Created from Add Function
DF17361 | 12 | Drake | Comedy | Frank | 12/2/2014 | 23/2/2014 | 10