C#•10mo ago

Properly understanding Public Static

^^^ title, I've got a test coming up, I avoided understanding this last test and skipped the optional questions with them ... I think I'd rather try to understand them now. And so, For example;

public static EX1(double x)
{
  return x*x;
}

public static EX1(double x)
{
  return x*x;
}

What purpose does "double x" serve us here? Or, better yet. if it were to be broken down by each syntax, used & explained. Sorry if it sounds like a dumb question, That's why I came here to ask! P.S if the code is missing something, I apologize ... our teacher makes us learn on pen and paper so I don't always know how to properly write stuff on a console app.

101 Replies

asianfxilureOP•10mo ago

another example would be.

public static EX2(int x);
{
if (x>0)
Console.WriteLine("1");
if (x<0)
Console.WriteLine("2");
if (x=0)
Console.WriteLine("3");
}

public static EX2(int x);
{
if (x>0)
Console.WriteLine("1");
if (x<0)
Console.WriteLine("2");
if (x=0)
Console.WriteLine("3");
}

leowest•10mo ago

the ; at the end of each if line essentially terminates your if condition there so u dont want it there for the ifs

asianfxilureOP•10mo ago

oh right yeah, sorry. aint paying much attention 😭 a bit tired since i've been studying for awhile

leowest•10mo ago

public -- The public keyword is an access modifier which is the most permissive access level.

static -- The static modifier is used to declare a static member which can be access from anywhere dependign on the outer class access level.

EX1 -- the method name

(double x) -- the parameters it can take, in your example it takes a parameter of the type double named x

{ -- brackets indicate the body of the method start

  return x*x; -- what it returns in this case it returns double

} -- brackets indicate the body of the method ends

public -- The public keyword is an access modifier which is the most permissive access level.

static -- The static modifier is used to declare a static member which can be access from anywhere dependign on the outer class access level.

EX1 -- the method name

(double x) -- the parameters it can take, in your example it takes a parameter of the type double named x

{ -- brackets indicate the body of the method start

  return x*x; -- what it returns in this case it returns double

} -- brackets indicate the body of the method ends

another thing you're missing in your code is the return type

public static double EX1(double x)

public static double EX1(double x)

another example that lacks the return type

leowest•10mo ago

https://learn.microsoft.com/en-us/dotnet/csharp/methods

Methods - C# Guide - C#

Overview of methods, method parameters, and method return values

leowest•10mo ago

and https://www.geeksforgeeks.org/c-sharp-methods/

GeeksforGeeks

C# | Methods - GeeksforGeeks

A Computer Science portal for geeks. It contains well written, well thought and well explained computer science and programming articles, quizzes and practice/competitive programming/company interview Questions.

leowest•10mo ago

asianfxilureOP•10mo ago

So for example if i returned X here, id return X in the form of int? or am i getting this wrong

leowest•10mo ago

anything u return from that method must be an int

Angius•10mo ago

The method return type denotes what the method returns There's no "in the form of"

leowest•10mo ago

that is what the return type defines

Angius•10mo ago

The method says it returns an int, so you must return an int

asianfxilureOP•10mo ago

aahhh, okay. and one more question i think. when we saayy:

public static ex1(int x,int y,int z)

public static ex1(int x,int y,int z)

the x,y,z are the parameters INSIDE the "ex1" method? which is also a public method?

Angius•10mo ago

They are the parameters of the ex1 method, yes

leowest•10mo ago

again u're missing the return type

Angius•10mo ago

It is also public, yes

asianfxilureOP•10mo ago

OH yeah. thank you

leowest•10mo ago

also dont make static an habit, for the sake of explaining its fine but static everything is no bueno

asianfxilureOP•10mo ago

unfortunately by my teacher static is everything right now

Angius•10mo ago

Oof

asianfxilureOP•10mo ago

his way of teaching is kinda wack

Angius•10mo ago

Teachers, man Worst programmers there are lmao

leowest•10mo ago

as long as you understand its not its fine u may use it a lot in console apps until u learn OOP etc

asianfxilureOP•10mo ago

like i dont even know how to use public on a console app bc it just errors out for me he teaches very like

leowest•10mo ago

show an example of how you're using it

asianfxilureOP•10mo ago

poorly 😭

Angius•10mo ago

Uh, no, making a method public should not be causing any errors

leowest•10mo ago

I would assume you're trying to declare a local variable with public and thus causing the error

Angius•10mo ago

Or a local function My suspicion as well

leowest•10mo ago

i.e.:

static void Main()
{
    // wrong and will not work but seems what u mentioned above.
    public int number = 0;
}

static void Main()
{
    // wrong and will not work but seems what u mentioned above.
    public int number = 0;
}

Angius•10mo ago

Yeah Local variables are local

leowest•10mo ago

because access modifiers have their own place in the scope

Angius•10mo ago

They cannot be public, private, protected, or internal

asianfxilureOP•10mo ago

or when i use SOME thing i may be mistaken about if its that one, but the console app suggests a "using class sm sm console" i dont really remember, and even applying it then it doesnt work. i havent learned classes yet

Angius•10mo ago

Access modifiers talk about the member's accessibility from outside of the class

asianfxilureOP•10mo ago

well, he hasnt taught us them *

Angius•10mo ago

A method is not a class So access modifiers on elements local to the method make no sense

static void Main()
{
    int number = 0;
}

static void Main()
{
    int number = 0;
}

asianfxilureOP•10mo ago

and we dont even touch computers yet in his class while we're surrounded by them, really frustrating.

leowest•10mo ago

static void Main()
{
    using (var fs = new StreamWriter(...))
    {
    
    }
}

static void Main()
{
    using (var fs = new StreamWriter(...))
    {
    
    }
}

this for example?

asianfxilureOP•10mo ago

Uuhm, nope i havent a clue what variety is yet.

Angius•10mo ago

I assume imports, so using System.Foo.Bar.Baz;

asianfxilureOP•10mo ago

Ah, well i must be mistaken then but thank you.

Angius•10mo ago

I would recommend $helloworld

MODiX•10mo ago

Interactive course https://learn.microsoft.com/en-us/training/paths/get-started-c-sharp-part-1/ Videos https://dotnet.microsoft.com/learn/videos

Angius•10mo ago

The teacher might be a waste of oxygen, but it doesn't mean you can't learn on your own

leowest•10mo ago

https://learn.microsoft.com/en-us/shows/csharp-fundamentals-for-absolute-beginners/ or if u prefer videos, personally watch those for the sake of suggesting something to people. they are short but concise videos about specific parts and the person talking is good at explaining what is going on

asianfxilureOP•10mo ago

ahah, a bit yeah. i do learn on my own sometimes! i used to use sololearn back when we learned python, its HORRIBLE for c# though (well, in my experience .. its really confusing and vague.) i had a head start and actually scored a pefect 100 on my first test, i assume Microsoft is a good source? ive come across a few pages of theirs when i was trying to figure out something and it didnt make much sense to me, dont think its their fault though. was awhile ago though so i dont remember what it really was. i will check that out aswell, thank you!

Angius•10mo ago

Well, yes, Microsoft made C# and .NET If there was ever a good resource on learning those, it would be Microsoft lol

leowest•10mo ago

just keep in mind, learning the language takes a lot of practice and repetition, so u learn 1 thing, open a console project, practice using what u have learned if u dont understand it, u ask questions the important is to be able to digest and use what u learned otherwise it will be as if u only looked thru it to soon forget and when u actually need it u no longer know the idea is, to not take too much at once, u learned about string manipulation? then go practice it a bit, see it working, see what u dont understand etc

asianfxilureOP•10mo ago

Oh, darn. honestly stupid to admit, but i didnt know they made it 😭 I dont really know any knowledge about c# outside of the actual coding experience itself

Angius•10mo ago

As a side note, you say you haven't used computers. I assume you're writing code on paper, 1997-style? If so, I highly recommend you do use the computer at home, and do try to run your code

asianfxilureOP•10mo ago

mhm! thats what i always try to do, and when it fails on my own i usually just ask other people on here, really love asking because theyre really helpful. :) yep, in class. although at home ive already got C# fitted on vsc community use it all the time.

Angius•10mo ago

VSC or VS Community? Two different things

asianfxilureOP•10mo ago

uuuah. the purple one 😭

Angius•10mo ago

VS, then Visual Studio 2022 Community

asianfxilureOP•10mo ago

right , yeah mixed them up

leowest•10mo ago

yeah VS 2022 is the good one to get started with

asianfxilureOP•10mo ago

alright, yeah. seems ive garbled public static a bit in my brain previously and failed to understand it, i'll attempt to solve in a bit after i eat some food. but thank you all so far. ^^

asianfxilureOP•10mo ago

public static double EX1(double x)
{
    return x*x;
}

public static double EX1(double x)
{
    return x*x;
}

asianfxilureOP•10mo ago

this is i THINK what i was previously talking about.

Angius•10mo ago

Where is this method? It's inside of another one, isn't it?

asianfxilureOP•10mo ago

it's just, out in the open really. it's not inside anything i atleast don't think so..?

asianfxilureOP•10mo ago

Angius•10mo ago

Show the whole file Ah This is a top-level statements file It's treated as the inside of the Main method, to put it simply So this is treated as a local method And, as we already know, it makes no sense for local members to have access modifiers

asianfxilureOP•10mo ago

how would you explain local members exactly? are they basically "local code" in a nutshell? compared to public and private codes?

Angius•10mo ago

This code compiles to, more or less

public class Program
{
    public static void Main()
    {
        public static double EX1(double x)
        {
            return x * x;
        }
    }
}

public class Program
{
    public static void Main()
    {
        public static double EX1(double x)
        {
            return x * x;
        }
    }
}

Local to a method So, being inside of the method

asianfxilureOP•10mo ago

OHH okay.

Angius•10mo ago

Class members can have access modifiers on their members, since they can be accessed from outside of that class and we need to control how

asianfxilureOP•10mo ago

so, what we've done here is created the class "program" to subject the method to it? well, i don't knoww if i worded it correctly exactly as i have barely any idea how any of this works. (due to studying on paper.)

Angius•10mo ago

Compiler takes the contents of the file and wraps them in a class and a Main method

asianfxilureOP•10mo ago

so it's, a hierachy?

Angius•10mo ago

$structure

MODiX•10mo ago

namespace Namespace;

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

    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;    

    public int PublicProperty { get; set; }

    public Class() {} // Constructor

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

Angius•10mo ago

Yes Namespace -> class -> method That'd be the basic of it Methods can have local methods Classes can have inner classes But for the most part, it's namespace -> class -> method Or, more aptly, namespace -> class -> class member

asianfxilureOP•10mo ago

wow that's really. interesting how deep it can go i think i should pick this up on my own sometime, get ahead of whenever my teacher decides to teach it. what would you call this entire.. thing? structure types? Oh , no that's something else ..

Angius•10mo ago

Not sure it has a name like that It's just... the program's structure? It consists of classes, classes can have members, etc

asianfxilureOP•10mo ago

oh right yeah. i mistook it for something else. found rsources from microsoft about it. Haang on, is this one supposed to work with a top-level statement file?

Angius•10mo ago

Using this code will make the file no longer a top-level statement file Since it has a class now, and one of the accepted entrypoint methods $mains

MODiX•10mo ago

The possible signatures for Main are

public static void Main() { }
public static int Main() { }
public static void Main(string[] args) { }
public static int Main(string[] args) { }
public static async Task Main() { }
public static async Task<int> Main() { }
public static async Task Main(string[] args) { }
public static async Task<int> Main(string[] args) { }

public static void Main() { }
public static int Main() { }
public static void Main(string[] args) { }
public static int Main(string[] args) { }
public static async Task Main() { }
public static async Task<int> Main() { }
public static async Task Main(string[] args) { }
public static async Task<int> Main(string[] args) { }

public is not required (can be any accessibility). Top-level statements are compiled into a Main method and will use an appropriate signature depending on the body. https://docs.microsoft.com/en-US/dotnet/csharp/fundamentals/program-structure/main-command-line

Main() and command-line arguments - C#

Learn about Main() and command-line arguments. The 'Main' method is the entry point of an executable program.

asianfxilureOP•10mo ago

it seems to drop the same error again, that's why i had asked.

asianfxilureOP•10mo ago

Angius•10mo ago

Ah Right This was what your code would compile into And thus, would throw an error But now it's clearer to see that EX1 is local to Main A proper, working example would be either

public class Program
{
    public static void Main()
    {
        double EX1(double x)
        {
            return x * x;
        }
    }
}

public class Program
{
    public static void Main()
    {
        double EX1(double x)
        {
            return x * x;
        }
    }
}

public class Program
{
    public static void Main()
    {
    }

    public static double EX1(double x)
    {
        return x * x;
    }
}

public class Program
{
    public static void Main()
    {
    }

    public static double EX1(double x)
    {
        return x * x;
    }
}

First one uses a proper local method (which is unorthodox but not unheard of) The other has the method as a class member

asianfxilureOP•10mo ago

Bare with me, but i am SO confused right now.

Angius•10mo ago

What about?

asianfxilureOP•10mo ago

One second. So,

public static double EX1(double x)
{
  return x*x;
}

public static double EX1(double x)
{
  return x*x;
}

is compiled by the computer, and read by it as this?

public class Program
{
    public static void Main()
    {
        public static double EX1(double x)
        {
            return x * x;
        }
    }
}

public class Program
{
    public static void Main()
    {
        public static double EX1(double x)
        {
            return x * x;
        }
    }
}

and.. i understand you've already given corrected versions of this, but basically. can you explain why it wouldn't work? just genuinely confused over it.

Angius•10mo ago

Yes, that's what it compiles to And it wouldn't work, because EX1 is a method local to the Main method Class members — like Main — need the access modifier to control how they can be accessed from the outside of the class. For example

var foo = new Foo();

var one = foo.Bar; // allowed, since `Bar` is `public`
var two = foo.Baz; // error, since `Baz` is `private`

class Foo
{
    public int Bar => 1;
    private int Baz => 2;
}

var foo = new Foo();

var one = foo.Bar; // allowed, since `Bar` is `public`
var two = foo.Baz; // error, since `Baz` is `private`

class Foo
{
    public int Bar => 1;
    private int Baz => 2;
}

So, things that are inside of a class can be visible to the outside, invisible to the outside, or even visible but only to the class's children Methods, meanwhile, keep everything local to them There's mo local method that can be public. There's no local method that can be private. There is no outside access to method's local code And thus, an access modifier cannot even be used for them Same reason why local methods cannot be static, since that also controls how the member is accessed from the outside, whether it's by class name or class instance. Local stuff is... local, it cannot be accessed, so static is useless anyway Thus, method's code — be it variables or local methods — cannot have either access modifiers or be static

asianfxilureOP•10mo ago

oh my god, that is SO mind boggling to process, but i think i get it.

Angius•10mo ago

Think of yourself as a method You live in a house (class) And you control access to the things in your house By putting a padlock on the fridge, but leaving the TV freely accessible

asianfxilureOP•10mo ago

mhm.

Angius•10mo ago

And punching anybody who wants to access you But your lungs, heart, and spleen are inside of you Local to you No need to put a padlock on your pancreas People can't access them anyway

asianfxilureOP•10mo ago

that's such a funny explanation, made me giggle a bit but it really helped. thank you. so,

public class Program
{
    public static void Main()
    {
    
        double EX1(double x)
        {
            return x * x;
        }
    }
}

public class Program
{
    public static void Main()
    {
    
        double EX1(double x)
        {
            return x * x;
        }
    }
}

this, works. no errors, is it FINE ? i don't know how to assign a value to the "double x" so im not sure if the output is correct.

Angius•10mo ago

EX1 is a method, so you need to call it for it to run For example,

public class Program
{
    public static void Main()
    {
        double result = EX1(67.99);
        Console.WriteLine($"The result is {result}");    

        double EX1(double x)
        {
            return x * x;
        }
    }
}

public class Program
{
    public static void Main()
    {
        double result = EX1(67.99);
        Console.WriteLine($"The result is {result}");    

        double EX1(double x)
        {
            return x * x;
        }
    }
}

asianfxilureOP•10mo ago

Waaittt, whaaat? it's like actual magic, how does that work?! and doesn't the order of them matter? (i ask this since it just.. well worked flawlessly. I'm confused specifically onn..

double result = EX1(67.99);

double result = EX1(67.99);

i understand result is a variable, and yes. we called the method. but, what exactly happens..?

Angius•10mo ago

No, order doesn't matter What happens, is that you pass 67.99 to the method, it gets placed in the x parameter Then the method does it's thing And returns a value That returned value can be saved in a variable

asianfxilureOP•10mo ago

oh my god that's actually so like, fascinating.

Angius•10mo ago

It's like a blender You input a banana and milk Blender does its thing You pour out a banana smoothie

asianfxilureOP•10mo ago

and out comes the smoothie.

Angius•10mo ago

Yep

asianfxilureOP•10mo ago

that's so gahhh i don't know, it just fascinates me i learned ALOT. i think that's all i've had to ask. i can't thank you enough. Well, I can. thank you so much bwahaha.

Angius•10mo ago

Anytime 👍

asianfxilureOP•10mo ago

Hope you have aa good day, whatever time it is for you. <3 I'll close this post now.

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Properly understanding Public Static