C#•17mo ago

❔ use of args in method

can someone explain the specific context in which we declare args in the methods? e.g. for this method - no args are declared whereas for another mtd where new variables are introduced, args are declared. Here's code:

public bool TransferTo(double amount, Account another)
    {
        bool isWithdrawOk = Withdraw(amount);

        if (isWithdrawOk)
        {
            another.Deposit(amount);
            return true;
        }
        else return false;
    }

public bool TransferTo(double amount, Account another)
    {
        bool isWithdrawOk = Withdraw(amount);

        if (isWithdrawOk)
        {
            another.Deposit(amount);
            return true;
        }
        else return false;
    }

public void CreditInterest()
    {
        var interest = CalculateInterest();
        Deposit(interest);
    }

public void CreditInterest()
    {
        var interest = CalculateInterest();
        Deposit(interest);
    }

32 Replies

Angius•17mo ago

You want arguments when you need to pass something into the method If the method doesn't take any input, you don't need arguments

moshimoshi•17mo ago

ahhh - is that the only context where args are needed? when passing input into method?

Pobiega•17mo ago

Thats literally what they do 🙂

moshimoshi•17mo ago

Got it! 🙂

Pobiega•17mo ago

Example: I want to write a method that gets me the chinese zodiac sign for a given year Would this method need an argument?

moshimoshi•17mo ago

Im thinking yes - since we need to input zodiac info?

Angius•17mo ago

You need to input the year

moshimoshi•17mo ago

ahhh right I also have another question, I dont really understand the use of the constructors here (it seems like unnecessary double work) - is it 'right' to completely omit it?

public class Account
{
    private string acctNumber; //attributes 
    private string acctHolderID;
    private double balance;

    public Account(string number, string holder, double bal)
    {
        acctNumber = number; //constructors 
        acctHolderID = holder;
        balance = bal;
    }

    public string AccountNumber //properties 
    {
        get
        {
            return acctNumber;
        }
    }

    public string AccountHolderID
    {
        get
        {
            return acctHolderID;
        } set
        {
            acctHolderID = value;
        }
    }

    public double Balance
    {
        get
        {
            return balance;
        } set
        {
            balance = value;
        }
    }

    public void Deposit(double amount)
    {
        balance += amount;
    }

    public virtual bool Withdraw(double amount)
    {
        balance -= amount;
        return true;
    }

    public bool TransferTo(double amount, Account another)
    {
        bool isWithdrawOk = Withdraw(amount);

        if (isWithdrawOk)
        {
            another.Deposit(amount);
            return true;
        }
        else return false;
    }

    public virtual double CalculateInterest()
    {
        return 0;
    }

    public void CreditInterest()
    {
        var interest = CalculateInterest();
        Deposit(interest);
    }
}

public class Account
{
    private string acctNumber; //attributes 
    private string acctHolderID;
    private double balance;

    public Account(string number, string holder, double bal)
    {
        acctNumber = number; //constructors 
        acctHolderID = holder;
        balance = bal;
    }

    public string AccountNumber //properties 
    {
        get
        {
            return acctNumber;
        }
    }

    public string AccountHolderID
    {
        get
        {
            return acctHolderID;
        } set
        {
            acctHolderID = value;
        }
    }

    public double Balance
    {
        get
        {
            return balance;
        } set
        {
            balance = value;
        }
    }

    public void Deposit(double amount)
    {
        balance += amount;
    }

    public virtual bool Withdraw(double amount)
    {
        balance -= amount;
        return true;
    }

    public bool TransferTo(double amount, Account another)
    {
        bool isWithdrawOk = Withdraw(amount);

        if (isWithdrawOk)
        {
            another.Deposit(amount);
            return true;
        }
        else return false;
    }

    public virtual double CalculateInterest()
    {
        return 0;
    }

    public void CreditInterest()
    {
        var interest = CalculateInterest();
        Deposit(interest);
    }
}

Pobiega•17mo ago

constructors?

Angius•17mo ago

Constructor is there to ensure the values are set when creating an instance of this class

Pobiega•17mo ago

public Account(string number, string holder, double bal)
    {
        acctNumber = number; //constructors 
        acctHolderID = holder;
        balance = bal;
    }

public Account(string number, string holder, double bal)
    {
        acctNumber = number; //constructors 
        acctHolderID = holder;
        balance = bal;
    }

is your only constructor here

moshimoshi•17mo ago

yeap - thats the one im reeferrng to

Angius•17mo ago

What is questionable, though, is the use of properties with backing fields instead of autoproperties

moshimoshi•17mo ago

what do you mean!

Angius•17mo ago

Also, those are fields, not attributes

Angius•17mo ago

$structure

MODiX•17mo ago

namespace Namespace;

[Attribute]
public class Class
{
  public string PublicField;
  private bool _privateField;
  protected double protectedField;    

  public int PublicProperty { get; set; }

  public Class() {} // Constructor

  public void Method(int parameter)
  {
    var localVariable = parameter; 
  } 
}

namespace Namespace;

[Attribute]
public class Class
{
  public string PublicField;
  private bool _privateField;
  protected double protectedField;    

  public int PublicProperty { get; set; }

  public Class() {} // Constructor

  public void Method(int parameter)
  {
    var localVariable = parameter; 
  } 
}

For C# versions older than 10, see $StructureOld

Angius•17mo ago

$getsetdevolve

MODiX•17mo ago

class Foo
{
    private int _bar;

    public int GetBar()
    {
        return _bar;
    }

    public void SetBar(int bar)
    {
        _bar = bar;
    }
}

class Foo
{
    private int _bar;

    public int GetBar()
    {
        return _bar;
    }

    public void SetBar(int bar)
    {
        _bar = bar;
    }
}

can be shortened to

class Foo
{
    private int _bar;

    public int GetBar() => _bar;

    public void SetBar(int bar) => _bar = bar;
}

class Foo
{
    private int _bar;

    public int GetBar() => _bar;

    public void SetBar(int bar) => _bar = bar;
}

can be shortened to

class Foo
{
    private int _bar;
    public int Bar {
        get { return _bar; }
        set { _bar = value; }
    }
}

class Foo
{
    private int _bar;
    public int Bar {
        get { return _bar; }
        set { _bar = value; }
    }
}

can be shortened to

class Foo
{
    private int _bar;
    public int Bar {
        get => _bar;
        set => _bar = value;
    }
}

class Foo
{
    private int _bar;
    public int Bar {
        get => _bar;
        set => _bar = value;
    }
}

can be shortened to

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

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

Pobiega•17mo ago

But yeah, a contructor (commonly called a ctor) has one responsibility: Make sure your object has a "valid state" when it is created. can an account exist without an account number?

moshimoshi•17mo ago

nope

Pobiega•17mo ago

okay, then it MUST always have an account number so a constructor is a good way to guarantee that

moshimoshi•17mo ago

i see, and the 'number', 'holder' and 'bal' fields are just used as placeholders in this instance?

acctNumber = number; //constructors 
        acctHolderID = holder;
        balance = bal;

acctNumber = number; //constructors 
        acctHolderID = holder;
        balance = bal;

Pobiega•17mo ago

they are method arguments 🙂 they are values passed in to the constructor if your ctor doesnt do anything with them, they do nothing.

moshimoshi•17mo ago

why cant i do this

acctNumber = ""; //constructors 
        acctHolderID = "";
        balance = 0;

acctNumber = ""; //constructors 
        acctHolderID = "";
        balance = 0;

Pobiega•17mo ago

you can, but now you have an account with no account number or well, a blank strink is the account number. not a great number.

moshimoshi•17mo ago

got it! Thanks so much!!! another question, if i were to use to auto 'get' 'set' property, how will the system know which variable im pointing to without explicitly calling it out?

public class Account
{
    private string acctNumber; //attributes 
    private string acctHolderID;
    private double balance;

    public Account(string number, string holder, double bal)
    {
        acctNumber = number; //constructors 
        acctHolderID = holder;
        balance = bal;
    }

    public string AccountNumber { get; }
public string AccountHolderID { get; set; }
public double Balance { get; set; }

    public void Deposit(double amount)
    {
        balance += amount;
    }

    public virtual bool Withdraw(double amount)
    {
        balance -= amount;
        return true;
    }

    public bool TransferTo(double amount, Account another)
    {
        bool isWithdrawOk = Withdraw(amount);

        if (isWithdrawOk)
        {
            another.Deposit(amount);
            return true;
        }
        else return false;
    }

    public virtual double CalculateInterest()
    {
        return 0;
    }

    public void CreditInterest()
    {
        var interest = CalculateInterest();
        Deposit(interest);
    }
}

public class Account
{
    private string acctNumber; //attributes 
    private string acctHolderID;
    private double balance;

    public Account(string number, string holder, double bal)
    {
        acctNumber = number; //constructors 
        acctHolderID = holder;
        balance = bal;
    }

    public string AccountNumber { get; }
public string AccountHolderID { get; set; }
public double Balance { get; set; }

    public void Deposit(double amount)
    {
        balance += amount;
    }

    public virtual bool Withdraw(double amount)
    {
        balance -= amount;
        return true;
    }

    public bool TransferTo(double amount, Account another)
    {
        bool isWithdrawOk = Withdraw(amount);

        if (isWithdrawOk)
        {
            another.Deposit(amount);
            return true;
        }
        else return false;
    }

    public virtual double CalculateInterest()
    {
        return 0;
    }

    public void CreditInterest()
    {
        var interest = CalculateInterest();
        Deposit(interest);
    }
}

Pobiega•17mo ago

remove your attributes they are actually fields "auto-properties" dont need explicit fields, they make their own

public class Account
{
    public Account(string accountNumber, string accountHolder, double balance)
    {
        AccountNumber = accountNumber;
        AccountHolderId = accountHolder;
        Balance = balance;
    }

    public string AccountNumber { get; }

    // public set? Should this really be changeable from outside the account? `private set;` feels better
    public string AccountHolderId { get; set; }

    public double Balance { get; private set; }

    public void Deposit(double amount)
    {
        Balance += amount;
    }

    public virtual bool Withdraw(double amount)
    {
        Balance -= amount;
        return true;
    }

    public bool TransferTo(double amount, Account another)
    {
        bool isWithdrawOk = Withdraw(amount);

        if (!isWithdrawOk) return false;

        another.Deposit(amount);
        return true;
    }

    public virtual double CalculateInterest()
    {
        return 0;
    }

    public void CreditInterest()
    {
        var interest = CalculateInterest();
        Deposit(interest);
    }
}

public class Account
{
    public Account(string accountNumber, string accountHolder, double balance)
    {
        AccountNumber = accountNumber;
        AccountHolderId = accountHolder;
        Balance = balance;
    }

    public string AccountNumber { get; }

    // public set? Should this really be changeable from outside the account? `private set;` feels better
    public string AccountHolderId { get; set; }

    public double Balance { get; private set; }

    public void Deposit(double amount)
    {
        Balance += amount;
    }

    public virtual bool Withdraw(double amount)
    {
        Balance -= amount;
        return true;
    }

    public bool TransferTo(double amount, Account another)
    {
        bool isWithdrawOk = Withdraw(amount);

        if (!isWithdrawOk) return false;

        another.Deposit(amount);
        return true;
    }

    public virtual double CalculateInterest()
    {
        return 0;
    }

    public void CreditInterest()
    {
        var interest = CalculateInterest();
        Deposit(interest);
    }
}

something like this 🙂

moshimoshi•17mo ago

Got it - this makes perfect sense! Alsoo, i wanted to look for practice questions related to object oriented programming - specifically around inheritence and polymorphism - are there any repositiories you recommend? 🙂

Pobiega•17mo ago

Not that specific, no.

moshimoshi•17mo ago

no worries! 😄

Accord•17mo 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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❔ use of args in method