C#•2y ago

❔ OOP Help

BankAccount.cs

namespace Classes;

public class BankAccount
{
    // These are fields / properties / characteristics
    public string Number { get; set; }
    public string Owner { get; set; }
    public decimal Balance {
        get
        {
            decimal balance = 0;
            foreach (var item in allTransactions)
            {
                balance += item.Amount;
            }
            return balance;
        }
    }
    
    // private = it can only be accessed by the code in THIS class (BankAccount)
    // static = this is shared by all of the BankAccount objects
    private static int accountNumberSeed = 1234567890;

    private List<Transaction> allTransactions = new List<Transaction>();

    // This is a constructor to assign values / initialize objects of this class type
    public BankAccount(string name, decimal initialBalance)
    {
        Number = accountNumberSeed.ToString();
        accountNumberSeed++;

        Owner = name;
        // MakeDeposit(initialBalance, DateTime.Now, "Initial balance");
    }

    // These are methods 
    public void MakeDeposit(decimal amount, DateTime date, string note)
    {
        if (amount <= 0)
        {
            throw new ArgumentOutOfRangeException(nameof(amount), "Amount of deposit must be positive");
            var deposit = new Transaction(amount, date, note);
            allTransactions.Add(deposit);
        }
    }

    public void MakeWithdrawal(decimal amount, DateTime date, string note)
    {
        if (amount <= 0)
        {
            throw new ArgumentOutOfRangeException(nameof(amount), "Amount of withdrawal must be positive");
        }
        if (Balance - amount < 0)
        {
            throw new InvalidOperationException("Not enough sufficient funds for this withdrawal");
        }
        var withdrawal = new Transaction(-amount, date, note);
        allTransactions.Add(withdrawal);
    }
}

namespace Classes;

public class BankAccount
{
    // These are fields / properties / characteristics
    public string Number { get; set; }
    public string Owner { get; set; }
    public decimal Balance {
        get
        {
            decimal balance = 0;
            foreach (var item in allTransactions)
            {
                balance += item.Amount;
            }
            return balance;
        }
    }
    
    // private = it can only be accessed by the code in THIS class (BankAccount)
    // static = this is shared by all of the BankAccount objects
    private static int accountNumberSeed = 1234567890;

    private List<Transaction> allTransactions = new List<Transaction>();

    // This is a constructor to assign values / initialize objects of this class type
    public BankAccount(string name, decimal initialBalance)
    {
        Number = accountNumberSeed.ToString();
        accountNumberSeed++;

        Owner = name;
        // MakeDeposit(initialBalance, DateTime.Now, "Initial balance");
    }

    // These are methods 
    public void MakeDeposit(decimal amount, DateTime date, string note)
    {
        if (amount <= 0)
        {
            throw new ArgumentOutOfRangeException(nameof(amount), "Amount of deposit must be positive");
            var deposit = new Transaction(amount, date, note);
            allTransactions.Add(deposit);
        }
    }

    public void MakeWithdrawal(decimal amount, DateTime date, string note)
    {
        if (amount <= 0)
        {
            throw new ArgumentOutOfRangeException(nameof(amount), "Amount of withdrawal must be positive");
        }
        if (Balance - amount < 0)
        {
            throw new InvalidOperationException("Not enough sufficient funds for this withdrawal");
        }
        var withdrawal = new Transaction(-amount, date, note);
        allTransactions.Add(withdrawal);
    }
}

54 Replies

GIGA BRAINOP•2y ago

Hi I'm following this tutorial on OOP from Microsoft, but for some reason my initialBalance is not being updated with the correct value even though I have the right parameters for the function. I've been looking through the code but can't seem to figure out what is wrong. Can someone help me out please? Program.cs

using Classes;

var account = new BankAccount("Josh", 100000);
Console.WriteLine($"Account {account.Number} was created for {account.Owner} with a starting balance of ${account.Balance}.");

account.MakeWithdrawal(500, DateTime.Now, "Rent payment");
Console.WriteLine(account.Balance);
account.MakeDeposit(100, DateTime.Now, "Friend paid me back");
Console.WriteLine(account.Balance);

using Classes;

var account = new BankAccount("Josh", 100000);
Console.WriteLine($"Account {account.Number} was created for {account.Owner} with a starting balance of ${account.Balance}.");

account.MakeWithdrawal(500, DateTime.Now, "Rent payment");
Console.WriteLine(account.Balance);
account.MakeDeposit(100, DateTime.Now, "Friend paid me back");
Console.WriteLine(account.Balance);

Angius•2y ago

I don't see you ever update initialBalance

GIGA BRAINOP•2y ago

Transaction.cs

namespace Classes;

public class Transaction
{
    // These are fields, or data elements to enforce validation or other rules
    public decimal Amount { get; }
    public DateTime Date { get; }
    public string Notes { get; }

    // This is a constructor to assign values / initialize objects of this class type
    public Transaction(decimal amount, DateTime date, string note)
    {
        Amount = amount;
        Date = date;
        Notes = note;
    }


}

namespace Classes;

public class Transaction
{
    // These are fields, or data elements to enforce validation or other rules
    public decimal Amount { get; }
    public DateTime Date { get; }
    public string Notes { get; }

    // This is a constructor to assign values / initialize objects of this class type
    public Transaction(decimal amount, DateTime date, string note)
    {
        Amount = amount;
        Date = date;
        Notes = note;
    }


}

uhh let me look for that

Angius•2y ago

If you want some value to be updated... you need to update it

GIGA BRAINOP•2y ago

am I not updating it with the makedeposit function?

Angius•2y ago

No Value types get passed by value, copied if you will Reference types get passed by reference, where updating one updates all $refvsvalue

MODiX•2y ago

https://cdn.discordapp.com/attachments/364492811489509376/692833980650881084/pass-by-reference-vs-pass-by-value-animation.gif

MODiX•2y ago

Angius#1586

REPL Result: Success

void TryUpdate(int x)
{
  x = 420;
}

var num = 69;
TryUpdate(num);
num

void TryUpdate(int x)
{
  x = 420;
}

var num = 69;
TryUpdate(num);
num

Result: int

Compile: 475.810ms | Execution: 28.738ms | React with ❌ to remove this embed.

GIGA BRAINOP•2y ago

that makes sense

MODiX•2y ago

Angius#1586

REPL Result: Success

class Foo { public int Val { get; set; } }

void TryUpdate(Foo f)
{
    f.Val = 420;
}

var num = new Foo { Val = 69 };
TryUpdate(num);
num

class Foo { public int Val { get; set; } }

void TryUpdate(Foo f)
{
    f.Val = 420;
}

var num = new Foo { Val = 69 };
TryUpdate(num);
num

Result: Foo

{
  "val": 420
}

{
  "val": 420
}

Compile: 501.797ms | Execution: 45.733ms | React with ❌ to remove this embed.

Angius•2y ago

And for reference types it works

GIGA BRAINOP•2y ago

i dont understand where i'm not updating initialBalance though

Angius•2y ago

Well... you never update it

GIGA BRAINOP•2y ago

I initialize it with var account = new BankAccount("Josh", 100000);

Angius•2y ago

Yeah

GIGA BRAINOP•2y ago

ima try and figure out where i need to update it

Angius•2y ago

Using this constructor

    public BankAccount(string name, decimal initialBalance)
    {
        Number = accountNumberSeed.ToString();
        accountNumberSeed++;

        Owner = name;
        // MakeDeposit(initialBalance, DateTime.Now, "Initial balance");
    }

    public BankAccount(string name, decimal initialBalance)
    {
        Number = accountNumberSeed.ToString();
        accountNumberSeed++;

        Owner = name;
        // MakeDeposit(initialBalance, DateTime.Now, "Initial balance");
    }

GIGA BRAINOP•2y ago

Angius•2y ago

The constructor sets the number and the owner Doesn't set the balance

GIGA BRAINOP•2y ago

so I would do Balance = initialBalance right?

Angius•2y ago

Yep

GIGA BRAINOP•2y ago

but it doesn't work for some reason the tutorial had me delete that when i did this code:

Angius•2y ago

But... Balance property doesn't have a setter

GIGA BRAINOP•2y ago

i see how would i add the setter to it? the tutorial made the getter a method public decimal Balance { get { decimal balance = 0; foreach (var item in allTransactions) { balance += item.Amount; } return balance; } } i tried adding set; to the end but it wouldn't work

Angius•2y ago

You seem to store the balance of the account in a kinda hidden way, where you keep the list of all transactions, and calculate balance based on that So you'd need to create a new deposit transaction But then we run into issues with your withdrawal and deposit methods, in that they never add the transaction to the list of transactions They just create a new transaction and peace out

GIGA BRAINOP•2y ago

ok i'm trying to make sense of this i'll try and work on it some more

Angius•2y ago

Sure thing

GIGA BRAINOP•2y ago

alright so i kept looking at the microsoft tutorial and all my code was identical to it so I figured maybe it's for an older version of .net that isn't compatible with my version i'm. not sure if that's the case but anyways i decided to delete the get method inside of balance and i added a setter to it like you said and just had simple += and +- for the balance

GIGA BRAINOP•2y ago

GIGA BRAINOP•2y ago

the output works fine now, but i'm not sure how I would relate this to the list do you have any ideas on how I would add a calculation to a list?

Angius•2y ago

Well, you're not using a list now The previous code stored a list of transactions

GIGA BRAINOP•2y ago

facts

Angius•2y ago

Some added money, some removed money Calculating the balance is as simple as iterating over that list and summing up the money added and removed Setting balance... is not done You never set it, since the balance is an outcome of calculating the transactions

GIGA BRAINOP•2y ago

so to even get to iterating over the list in the first place, I would have to add entries to it that are negative (withdrawal) and positive (deposit)?

Angius•2y ago

yep

GIGA BRAINOP•2y ago

alright i'll work on that thanks for all the help btw

Angius•2y ago

Which you seem to do with

allTransactions.Add(deposit);

allTransactions.Add(deposit);

and

allTransactions.Add(withdrawal);

allTransactions.Add(withdrawal);

GIGA BRAINOP•2y ago

how would you know where to set up the functionality to calculate the balance? i think i have the adding to list functionality figured out, it just ended up being the same thing as the tutorial though lol

GIGA BRAINOP•2y ago

GIGA BRAINOP•2y ago

but like you said earlier the balance calculation was in a weird place

Angius•2y ago

You have the functionality to calculate balance in the getter of Balance it seems

GIGA BRAINOP•2y ago

yeah but didn't you say it was in a weird place?

Angius•2y ago

Not really It's fine to have it in the getter

GIGA BRAINOP•2y ago

so then it all comes back to the idea where my setter is messed up or me not updating the balance

Angius•2y ago

You don't ever update balance You don't need the setter You store the values in the list of transactions

GIGA BRAINOP•2y ago

Angius•2y ago

Then, the balance getter calculates it on the fly

GIGA BRAINOP•2y ago

so this isn't updating the balance?

Angius•2y ago

If it doesn't have a setter, then no, it doesn't If you want to keep the tutorial's way of storing transactions and calculating balance on the fly, what you need to do, is add a new deposit transaction with the initialbalance value That's how you store an initial amount of money in the account

GIGA BRAINOP•2y ago

im literally so dumb all the stuff you said makes sense now and the code works but i feel like its literally the same stuff i had before like in the tutorial

namespace Classes;

public class BankAccount
{
    // These are fields / properties / characteristics
    public string Number { get; }
    public string Owner { get; set; }
    public decimal Balance
    { 
        get
        {
            decimal balance = 0;
            foreach (var item in allTransactions)
            {
                balance += item.Amount;
            }
            return balance;
        }
    }
    
    // private = it can only be accessed by the code in THIS class (BankAccount)
    // static = this is shared by all of the BankAccount objects
    private static int accountNumberSeed = 1234567890;

    // This is a constructor to assign values / initialize objects of this class type
    public BankAccount(string name, decimal initialBalance)
    {
        Number = accountNumberSeed.ToString();
        accountNumberSeed++;
        Owner = name;
        MakeDeposit(initialBalance, DateTime.Now, "Initial balance");
    }
    private List<Transaction> allTransactions = new List<Transaction>();

    // These are methods 
    public void MakeDeposit(decimal amount, DateTime date, string note)
    {
        var deposit = new Transaction(amount, date, note);
        allTransactions.Add(deposit);
    }

    public void MakeWithdrawal(decimal amount, DateTime date, string note)
    {
        var withdrawal = new Transaction((amount * -1), date, note);
        allTransactions.Add(withdrawal);
    }
}

namespace Classes;

public class BankAccount
{
    // These are fields / properties / characteristics
    public string Number { get; }
    public string Owner { get; set; }
    public decimal Balance
    { 
        get
        {
            decimal balance = 0;
            foreach (var item in allTransactions)
            {
                balance += item.Amount;
            }
            return balance;
        }
    }
    
    // private = it can only be accessed by the code in THIS class (BankAccount)
    // static = this is shared by all of the BankAccount objects
    private static int accountNumberSeed = 1234567890;

    // This is a constructor to assign values / initialize objects of this class type
    public BankAccount(string name, decimal initialBalance)
    {
        Number = accountNumberSeed.ToString();
        accountNumberSeed++;
        Owner = name;
        MakeDeposit(initialBalance, DateTime.Now, "Initial balance");
    }
    private List<Transaction> allTransactions = new List<Transaction>();

    // These are methods 
    public void MakeDeposit(decimal amount, DateTime date, string note)
    {
        var deposit = new Transaction(amount, date, note);
        allTransactions.Add(deposit);
    }

    public void MakeWithdrawal(decimal amount, DateTime date, string note)
    {
        var withdrawal = new Transaction((amount * -1), date, note);
        allTransactions.Add(withdrawal);
    }
}

would you say this is good now?

Angius•2y ago

Yeah, LGTM

GIGA BRAINOP•2y ago

thank you very much 🙂

blinkbat•2y ago

just preference but I'd keep my constructor at the top of the class

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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