int main()
{
int accountNumber;
string lastName;
string firstName;
double balance;
fstream outCredit( "credit.dat", ios::in | ios::out | ios::binary );
// exit program if fstream cannot open file
if ( !outCredit )
{
cerr << "File could not be opened." << endl;
exit( EXIT_FAILURE );
} // end if
cout << "Enter account number (1 to 100, 0 to end input)\n? ";
// require user to specify account number
ClientData client;
cin >> accountNumber;
// user enters information, which is copied into file
while ( accountNumber > 0 && accountNumber <= 100 )
{
// user enters last name, first name and balance
cout << "Enter lastname, firstname, balance\n? ";
cin >> lastName;
cin >> firstName;
cin >> balance;
// set record accountNumber, lastName, firstName and balance values
client.setAccountNumber( accountNumber );
client.setLastName( lastName );
client.setFirstName( firstName );
client.setBalance( balance );
// seek position in file of user-specified record
outCredit.seekp( ( client.getAccountNumber() - 1 ) *
sizeof( ClientData ) );
// write user-specified information in file
outCredit.write( reinterpret_cast< const char * >( &client ),
sizeof( ClientData ) );
// enable user to enter another account
cout << "Enter account number\n? ";
cin >> accountNumber;
} // end while
} // end main
