#include <iostream>
using namespace std;

int accountNumber = 12345;
int pinNumber = 54321;
int balance = 0;

bool login () {

    int givenAccountNumber = -1;
    int givenPinNumber = -1;
    bool isAccountInvalid = true;
    bool isPinInvalid = true;

    cout << "Welcome!" << endl;

    while (isAccountInvalid) {

        cout << "Please enter your account number: ";
        cin >> givenAccountNumber;

        if (givenAccountNumber == accountNumber) {
            isAccountInvalid = false;
        } else {
            cout << "Invalid account number! Try again." << endl;
        }
    }

    while (isPinInvalid) {

        cout << "Enter your PIN: ";
        cin >> givenPinNumber;

        if (givenPinNumber == pinNumber) {
            isPinInvalid = false;
        } else {
            cout << "Invalid PIN number! Try again." << endl;
        }

    }

    return true;

}

int getUserOption () {

    int selectedOption = -1;

    cout << "Main menu:" << endl;
    cout << "   1 - View my balance" << endl;
    cout << "   2 - Withdraw cash" << endl;
    cout << "   3 - Deposit funds" << endl;
    cout << "   4 - Exit" << endl;
    cout << "Enter a choice: " << endl;
    cin >> selectedOption;

    return selectedOption;

}

void viewBalance () {

    cout << "You have:" << endl;
    cout << "$" << balance << endl;

}

void withdrawCash() {

    int selectedOption = -1;
    int valueToWithdraw = 0;
    bool isNotFinished = true;

    do {

        cout << "Withdrawal options:" << endl;
        cout << "1 - $20" << endl;
        cout << "2 - $40" << endl;
        cout << "3 - $60" << endl;
        cout << "4 - $100" << endl;
        cout << "5 - $200" << endl;
        cout << "6 - cancel transaction" << endl;
        cout << "choose a withdrawal option (1-6)" << endl;

        cin >> selectedOption;
        switch (selectedOption) {
            case 1:
                valueToWithdraw = 20;
                break;
            case 2:
                valueToWithdraw = 40;
                break;
            case 3:
                valueToWithdraw = 60;
                break;
            case 4:
                valueToWithdraw = 100;
                break;
            case 5:
                valueToWithdraw = 200;
                break;
            case 6:
                isNotFinished = false;
                break;
            default:
                cout << "Invalid option! Try again." << endl;
                break;
        }

        if (valueToWithdraw != 0) {
            if (valueToWithdraw > balance) {
                cout << "You just have $" << balance << ". You can't withdraw $" << valueToWithdraw << endl;
            } else {
                balance = balance - valueToWithdraw;
                isNotFinished = false;
            }
            valueToWithdraw = 0;
        }

    } while (isNotFinished);

}

void depositFunds() {

    int selectedOption = -1;
    bool isNotFinished = true;

    do {

        cout << "Deposit options:" << endl;
        cout << "1 - $20" << endl;
        cout << "2 - $40" << endl;
        cout << "3 - $60" << endl;
        cout << "4 - $100" << endl;
        cout << "5 - $200" << endl;
        cout << "6 - cancel transaction" << endl;
        cout << "choose a deposit option (1-6)" << endl;

        cin >> selectedOption;
        switch (selectedOption) {
            case 1:
                balance = balance + 20;
                isNotFinished = false;
                break;
            case 2:
                balance = balance + 40;
                isNotFinished = false;
                break;
            case 3:
                balance = balance + 60;
                isNotFinished = false;
                break;
            case 4:
                balance = balance + 100;
                isNotFinished = false;
                break;
            case 5:
                balance = balance + 200;
                isNotFinished = false;
                break;
            case 6:
                isNotFinished = false;
                break;
            default:
                cout << "Invalid option! Try again." << endl;
                break;
        }

    } while (isNotFinished);

}

int main () {

    if (login()) {

        int isNotFinished = true;

        do {

            switch (getUserOption()) {
                case 1:
                    viewBalance();
                    break;
                case 2:
                    withdrawCash();
                    break;
                case 3:
                    depositFunds();
                    break;
                case 4:
                    isNotFinished = false;
                    break;
                default:
                    cout << "Invalid option! Try again." << endl;
                    break;
            }

        } while (isNotFinished);

    }

    return 0;

}