Strange character in C++ program output - c++

Question

I am creating an ATM program in C++ for school and I'm using this project as an opportunity to begin learning the language. I am trying to output bank accounts to a text file in this format:
First Last
CardNumber
PinNumber
Balance
Originally it was outputting fine and then I developed a bunch of new methods etc. I didn't change any of the original code that has to do with outputting the bank account but now it's outputting strangely.
My output ends up being:
First Last
random letter or symbol
PinNumber
blank
Here is my code for creating a new bank account:
AccountHandler.h
#include <iostream>
#include <string>
using namespace std;
struct bankAccount //Create a new bank account type
{
string name;
string cardNum;
string balance;
string pin;
};
class AccountHandler
{
public:
AccountHandler();
~AccountHandler();
void withdraw(struct bankAccount acc, string amount);
void deposit(struct bankAccount acc);
int checkBalance(struct bankAccount acc);
void createAccount();
};
AccountHandler.cpp
void AccountHandler::createAccount() //creates a new bank account and stores in accounts.txt
{
ofstream accounts;
struct bankAccount newAcc;
string first, last;
string tempPin1, tempPin2;
if (!accounts.is_open())
{
accounts.open("accounts.txt", ofstream::app);
}
std::cout << "Thank you for choosing to bank with ATM406!\n\n";
std::cout << "Please enter the name for the account: ";
std::cin >> first >> last;
newAcc.name = first + " " + last;
while (true)
{
std::cout << "\nPlease enter a 4-digit pin for security: ";
std::cin >> tempPin1;
std::cout << "\nPlease re-enter your 4-digit pin for validation: ";
std::cin >> tempPin2;
if (tempPin1 == tempPin2) //PINS MATCH
{
newAcc.pin = tempPin1;
break;
}
else //PINS DO NOT MATCH
{
std::cout << "The pins did not match!" << std::endl;
}
}
//GENERATE A RANDOM 4-DIGIT NUMBER FOR CARDNUM
srand(time(NULL));
newAcc.cardNum = rand() % 9000 + 1000;
//STORE ACCOUNT IN FORMAT: NAME\nCARDNUM\nPIN\nBALANCE
accounts << newAcc.name << "\n" << newAcc.cardNum << "\n"
<< newAcc.pin << "\n" << newAcc.balance << "\n";
accounts.close();
std::cout << "\nAccount created with name: " << newAcc.name << " pin: " << newAcc.pin
<< ". Card number: " << newAcc.cardNum << "\n\n\n";
}
Thank you!

Answer 1

cardNum is a string, but you assign an integer to it. That converts the integer to a char (truncating it to a much smaller value) and stores it in the string.
balance is blank because it's an empty string, you never give the string a value.
N.B. the call to is_open() in createAccount is pointless, the fstream can't be open, because you just default-constructed it.