Help with streams

[lestro]

I'm trying to write a bank program, and I would like to save the accounts that are created and make them accessible by the pin number they chose. The program asks for a first and last name, a 4 digit pin number, and a starting balance. The program then is supposed to create a text file named after the pin they chose, and print their full name and their balance. Then, when they enter their pin again, the program is supposed to grab the full name and balance and store them in the variables. But the program pauses after you enter a pin. Can anyone help me with this?

#include <iostream>
#include <fstream>
#include <string>
#include <sstream>

using namespace std;

int main()
{
    while (1 == 1)
    {
        cout << "Welcome to the C++ bank." << endl;
        cout << endl;
        
        cout << "Do you have an account with us? \"Y\" or \"N\": ";
        string choice;
        cin >> choice;
        cout << endl;
        
        string fname;
        string lname;
        string fullname = fname + " " + lname;
        int pin;
        int balance = 0;
        
        if (choice == "N" || choice == "n")
        {
            cout << "Enter your first name: ";
            string fname;
            cin >> fname;
            cout << endl;
            
            cout << "Enter your last name: ";
            string lname;
            cin >> lname;
            cout << endl;
            
            string fullname = fname + " " + lname;
            
            cout << "Enter a 4 digit pin: ";
            int pin;
            cin >> pin;
            cout << endl;
            
            cout << "Enter your pin again: ";
            int pin2;
            cin >> pin2;
            cout << endl;
            
            while (pin < 1000 || pin2 < 1000)
            {
                cout << "Your pin was not 4 digits long. Please try again." << endl;
                cout << endl;
                
                cout << "Enter a 4 digit pin: ";
                cin >> pin;
                cout << endl;
                
                cout << "Enter your pin again: ";
                cin >> pin2;
                cout << endl;
            }
            
            while (pin > 9999 || pin2 > 9999)
            {
                cout << "Your pin was not 4 digits long. PLease try again." << endl;
                cout << endl;
                
                cout << "Enter a 4 digit pin: ";
                cin >> pin;
                cout << endl;
                
                cout << "Enter your pin again: ";
                cin >> pin2;
                cout << endl;
            }
            
            while (pin != pin2)
            {
                cout << "Your pins did not match. Please try again." << endl;
                cout << endl;
                
                cout << "Enter a 4 digit pin: ";
                cin >> pin;
                cout << endl;
                
                cout << "Enter your pin again: ";
                cin >> pin2;
                cout << endl;
            }
            
            cout << "Please deposit your starting balance: ";
            int balance;
            cin >> balance;
            cout << endl;
            
            cout << "If you would like to withdraw, type \"W\". If you would like to deposit, type \"D\". If you would like to log out press any key: ";
            cin >> choice;
            cout << endl;
            
            if (choice == "W" || choice == "w")
            {
                cout << "Enter the amount you want to withdraw: ";
                int wamount;
                cin >> wamount;
                cout << endl;
                
                while (balance < wamount)
                {
                    cout << "You have insufficient funds. Enter a different amount: ";
                    cin >> wamount;
                    cout << endl;
                }
                
                balance = balance - wamount;
                
                cout << "Your new balance is: " << balance << endl;
                cout << endl;
            }
            
            else if (choice == "D" || choice == "d")
            {
                cout << "Enter the amount you would like to deposit: ";
                int damount;
                cin >> damount;
                cout << endl;
                
                balance = balance + damount;
                
                cout << "Your new balance is: " << balance << endl;
                cout << endl;
                cout << endl;
            }
            
            ofstream out_file (to_string(pin) + ".txt");
            out_file << fullname << '\n';
            out_file << balance << '\n';
            out_file.close();
            
            
        }
        
        else if (choice == "Y" || choice == "y")
        {
            cout << "Enter your 4 digit pin: ";
            cin >> pin;
            cout << endl;
            
            string line;
            ifstream in_file (to_string(pin) + ".txt");
            if (in_file.is_open())
            {
                while (getline (in_file, line))
                {
                    cin >> line;
                    fullname = line;
                    cin >> line;
                    int result;
                    istringstream convert(line);
                    if ((!convert >> result))
                    {
                        result = 0;
                    }
                    balance = result;
                    
                    in_file.close();
                }
            }
            
            else
            {
                cout << "Sorry, you do not have an account." << endl;
                continue;
            }
            
            cout << "Welcome " << fullname << "." << endl;
            cout << endl;
            
            cout << "You have " << balance << " in your account" << endl;
            cout << endl;
            
            cout << "If you would like to withdraw, type \"W\". If you would like to deposit, type \"D\". If you would like to log out press any key: ";
            cin >> choice;
            cout << endl;
            
            if (choice == "W" || choice == "w")
            {
                cout << "Enter the amount you want to withdraw: ";
                int wamount;
                cin >> wamount;
                cout << endl;
                
                while (balance < wamount)
                {
                    cout << "You have insufficient funds. Enter a different amount: ";
                    cin >> wamount;
                    cout << endl;
                }
                
                balance = balance - wamount;
                
                cout << "Your new balance is: " << balance << endl;
                cout << endl;
            }
            
            else if (choice == "D" || choice == "d")
            {
                cout << "Enter the amount you would like to deposit: ";
                int damount;
                cin >> damount;
                cout << endl;
                
                balance = balance + damount;
                
                cout << "Your new balance is: " << balance << endl;
                cout << endl;
                
            }
            
            ofstream out_file (to_string(pin) + ".txt");
            out_file << fullname << '\n';
            out_file << balance << '\n';
            out_file.close();
            
        }
    }
}