C#•15mo ago

❔ Struct vs Class

When do i use a struct vs a class, There seems to be pretty much no difference between the two except for really small things, what i want is composition, so idk if that helps. i think a struct is waht i should use for that right?

71 Replies

sibber•15mo ago

reference vs value type is a big difference

Itskillerluc•15mo ago

why is it really that big of a deal

sibber•15mo ago

having a reference to something vs the thing itself changes a lot of things

Itskillerluc•15mo ago

like i dont rly understand what it would change

sibber•15mo ago

like how assignment works when you pass a class instance to a method, your actually passing a reference to the actual instance

Itskillerluc•15mo ago

well i know that so if you change it it changes everywhere

sibber•15mo ago

yes

Itskillerluc•15mo ago

and i imagine that doesnt happenw ith a struct then, but even then that doesnt sound like a big deal

sibber•15mo ago

structs on the other hand are copied it is structs have some other limitations too as a general rule of thumb, default to classes

Itskillerluc•15mo ago

so https://paste.ofcode.org/37PNwYAx6seZZWQt6MVij65 is this the way to do it? or should i do it a diff way oh ok i guess ill use a class then

Thinker•15mo ago

Unity's Vector2 and Vector3 are structs, because they essentially act as numbers. You wouldn't want to be able to change the x component of a vector and have that be reflected everywhere else that you've passed that vector to. Imagine for instance that you set an object's position to a vector, then you also pass that same vector to a method which saves it somewhere else. Now if something completely unrelated comes along and changes that vector, you really wouldn't want that to also change the position of the object.

Itskillerluc•15mo ago

oh ye i should use a class because i want to be able to change this variable

sibber•15mo ago

unless what you're writing represents a single logical value (and its size is relatively small), e.g. a date, a vector, etc

Itskillerluc•15mo ago

ah ye so this is wrongly used

sibber•15mo ago

yes

Thinker•15mo ago

What if you did

Vector3 vec = new Vector3(1, 2, 3);
transform.position = vec;
DoStuff(vec, "foo", bar); // Whoops, this method edited the vector, and now the transform.position has also changed!

Vector3 vec = new Vector3(1, 2, 3);
transform.position = vec;
DoStuff(vec, "foo", bar); // Whoops, this method edited the vector, and now the transform.position has also changed!

sibber•15mo ago

https://learn.microsoft.com/en-us/dotnet/standard/design-guidelines/choosing-between-class-and-struct

Choosing Between Class and Struct - Framework Design Guidelines

Learn how to decide whether to design a type as a class, or to design a type as a struct. Understand how reference types and value types differ in .NET.

Itskillerluc•15mo ago

i changed it to a class now is there a way to do what i did smalelr well

sibber•15mo ago

do what

Itskillerluc•15mo ago

public enum MovementType {Sprinting, Walking, Sneaking}

    [Serializable]
    public class Movement
    {
        public MovementType movementType;
        public float sprintSpeed;
        public float walkSpeed;
        public float sneakSpeed;

        public Movement(MovementType movementType, float sprintSpeed, float walkSpeed, float sneakSpeed)
        {
            this.movementType = movementType;
            this.sprintSpeed = sprintSpeed;
            this.walkSpeed = walkSpeed;
            this.sneakSpeed = sneakSpeed;
        }
    }

    public Movement movement = new(MovementType.Walking, 20, 10, 3);

public enum MovementType {Sprinting, Walking, Sneaking}

    [Serializable]
    public class Movement
    {
        public MovementType movementType;
        public float sprintSpeed;
        public float walkSpeed;
        public float sneakSpeed;

        public Movement(MovementType movementType, float sprintSpeed, float walkSpeed, float sneakSpeed)
        {
            this.movementType = movementType;
            this.sprintSpeed = sprintSpeed;
            this.walkSpeed = walkSpeed;
            this.sneakSpeed = sneakSpeed;
        }
    }

    public Movement movement = new(MovementType.Walking, 20, 10, 3);

that part

sibber•15mo ago

unrelated, but im not a fan of nesting types

Itskillerluc•15mo ago

wher am i nesting types

sibber•15mo ago

Movement is inside CharMovement

Itskillerluc•15mo ago

sibber•15mo ago

which should probably be called CharacterController

Itskillerluc•15mo ago

well ye but otherwise i have to create a new script and idk what to do with the script that arleady exists

sibber•15mo ago

oh well id think of a different name because this one is confusing anyway you don't you can just create a normal file

Itskillerluc•15mo ago

in unity?

sibber•15mo ago

yes

Itskillerluc•15mo ago

wait what 😮

sibber•15mo ago

unity c# is still c# just out of date and the unity api is weird but other than that

Itskillerluc•15mo ago

well if there are good alternatives for unity i could use that but the others seem way harder and more annoying like ofc there is unreal but no way that im gonna code in C++ bruh the C# naming conventions suck, public fields have the same conventions as public classes, im just gonna get duplicates now

sibber•15mo ago

you can used to it unreal c++ is a lot different from regular c++ from what ive heard but im not telling you not to use unity unity's fine

Itskillerluc•15mo ago

just not having garbage collections scares me

sibber•15mo ago

you can name fields the same as classes

Itskillerluc•15mo ago

no you cant it doesnt work

sibber•15mo ago

but unity's naming convention is different in regular apps we dont use public fields

Itskillerluc•15mo ago

wdym you use all getters and setters?

sibber•15mo ago

unity names all fields in camelCase anyway yes properties

Itskillerluc•15mo ago

they dumb tho like if im gonan have a getter and a setter, then why do i not just make it public tf

MODiX•15mo ago

Cyberrex#8052

REPL Result: Success

class C
{
    public Test Test;
}

class Test {}

class C
{
    public Test Test;
}

class Test {}

Compile: 408.569ms | Execution: 39.195ms | React with ❌ to remove this embed.

Itskillerluc•15mo ago

you can compile code

sibber•15mo ago

see it works

Itskillerluc•15mo ago

in discord???? oh

sibber•15mo ago

its a bot

Itskillerluc•15mo ago

its nested 💀

sibber•15mo ago

what is

Itskillerluc•15mo ago

FOR GOOD REASONS THO the class

sibber•15mo ago

because if at some point you decided to change the default getter and setter, you could

Itskillerluc•15mo ago

fair

sibber•15mo ago

but the main reason is to be consistent its not nested its defined below it

Itskillerluc•15mo ago

mine is nested though

sibber•15mo ago

oh i thought you were talking about the repl

Thinker•15mo ago

Because you may want to have logic in the getter/setter

cap5lut•15mo ago

getter and setters are a lot easier in c#

public class A {
  public int Value { get; set; }
}

public class A {
  public int Value { get; set; }
}

and u r done with having a getter and a setter, u can also have getters and initializers only { get; init; }, etc

Itskillerluc•15mo ago

oohhhh ohhhhhhh thats cooool intializer? just =?

Thinker•15mo ago

But Unity doesn't let you use them mmLul

cap5lut•15mo ago

a setter that u can use only once no init in unity? D:

Itskillerluc•15mo ago

oof

Thinker•15mo ago

outdated language version

Itskillerluc•15mo ago

idk my ide says i can do it and its like synched with unity

cap5lut•15mo ago

but in the end if u would have to add functionality to the getter/setter it becomes a bit more bloaty, but still not as much as java:

public class A
{
  private int _value;
  public int Value
  {
    get => _value;
    set
    {
      if (value > 255) throw new ArgumentException();
      _value = value;
    }
  }
}

public class A
{
  private int _value;
  public int Value
  {
    get => _value;
    set
    {
      if (value > 255) throw new ArgumentException();
      _value = value;
    }
  }
}

but this way u dont have breaking changes in the API itself also regarding nested classes: they work differently in c# than nested inner classes in java btw., as it wouldnt have automatically a reference to the outer instance.

public class A {
  public String name;
  public class B {
    String getOuterName() {
      return A.this; // this part doesnt exist in c#
    }
  }
}

public class A {
  public String name;
  public class B {
    String getOuterName() {
      return A.this; // this part doesnt exist in c#
    }
  }
}

Itskillerluc•15mo ago

lol

krazycay•15mo ago

yo question how can i detect when the console app is minimized

cap5lut•15mo ago

open separate thread for that question. its totally unrelated to this

Itskillerluc•15mo ago

bruh does C# also not have enhanced enums? nvm it does

Jimmacle•15mo ago

idk what an enhanced enum is

cap5lut•15mo ago

to have it sorta like java u could use extension methods, but i think its sorta ugly

public enum MovementType { Sprinting, Walking, Sneaking }
public static class MovementTypeExtensions
{
  public static float GetMovementSpeed(this MovementType type)
  {
    switch (type)
    {
      case MovementType.Sprinting: return 1.5f;
      case MovementType.Walking: return 1.0f;
      case MovementType.Sneaking: return 0.5f;
    }
    throw new Exception(); // dunno right now the best exception type to throw here
  }
}

public enum MovementType { Sprinting, Walking, Sneaking }
public static class MovementTypeExtensions
{
  public static float GetMovementSpeed(this MovementType type)
  {
    switch (type)
    {
      case MovementType.Sprinting: return 1.5f;
      case MovementType.Walking: return 1.0f;
      case MovementType.Sneaking: return 0.5f;
    }
    throw new Exception(); // dunno right now the best exception type to throw here
  }
}

which u could then use via MovementKind.Sprinting.GetMovementSpeed(); but something like this would be more c# like i would say:

public enum MovementKind { Sprinting, Walking, Sneaking }
public readonly struct MovementType
{
  public static readonly MovementType Sprinting = new MovementType(MovementKind.Sprinting, 1.5f);
  // for the other types

  public MovementKind Kind { get; }
  public float Speed { get; }

  private MovementType(MovementKind kind, float speed)
  {
    Kind = kind;
    Speed = speed;
  }
}

public enum MovementKind { Sprinting, Walking, Sneaking }
public readonly struct MovementType
{
  public static readonly MovementType Sprinting = new MovementType(MovementKind.Sprinting, 1.5f);
  // for the other types

  public MovementKind Kind { get; }
  public float Speed { get; }

  private MovementType(MovementKind kind, float speed)
  {
    Kind = kind;
    Speed = speed;
  }
}

Thinker•15mo ago

If you didn't notice, this is a post for a completely different question. Please open a new post in #help.

FusedQyou•15mo ago

Stuff like init is allowed but won't compile unless you add a sort of workaround, such as this:

using System.ComponentModel;

namespace System.Runtime.CompilerServices
{
    /// <summary>
    /// Reserved to be used by the compiler for tracking metadata.
    /// This class should not be used by developers in source code.
    /// </summary>
    [EditorBrowsable(EditorBrowsableState.Never)]
    internal static class IsExternalInit
    {
    }
}

using System.ComponentModel;

namespace System.Runtime.CompilerServices
{
    /// <summary>
    /// Reserved to be used by the compiler for tracking metadata.
    /// This class should not be used by developers in source code.
    /// </summary>
    [EditorBrowsable(EditorBrowsableState.Never)]
    internal static class IsExternalInit
    {
    }
}

Unity supports latest .NET Standard but stuff like init is not part of that, only .NET 6, 7 and 8

Accord•15mo 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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❔ Struct vs Class