Java Assignment

[pine tide]

I am being asked to declare two things named "integer fee" and "integer year" as private fields. What does that mean to delacire as private feilds? and how would I go about that.

[pine kelp]

<@&987246399047479336> please have a look, thanks.

[pine kelp]

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[stark edge]

so this is almost too easy of a question for us here

I want to get a sense of what you do understand at this point before responding

so can you share your assignment/what you've done so far?

[pine tide]

Just started this coding class towards my electrical engineering major. Teacher basically just had us subscribe to a course that has a bunch of assignments attached to it and said "do all these for your grades" so Im just going through some online course that doesnt give me too much detailed information. And when I get things wrong. It just says error. Im constantly finding myself watching youtube videos for all these things that seem so, as you said, easy. So far from youtube soley, I understand creating public classes, integers, and printing texts. Also giving things like set names.

[stark edge]

yeah so okay

lets start small here

class Thing {

}

a class declaration looks like this

[pine tide]

idk thats kinda a lot but Im honestly thinking of switching teachers if I can, I really feel like im just being given questions without any help and constantly watching youtube to help haha. But I thought I mine as well ask someone in this server for small help

[stark edge]

it is declaring a new "classification" of objects

[pine tide]

oh ok

[stark edge]

if objects of this classification hold data

then we need to put that data in "fields"

easy example

class Dog {
    String name;
}

all dogs have names

so the dog class would need to contain a field that can hold the name

Dog dog = new Dog();
dog.name = "Fido";

so dogs are "boxes" that can hold a name

pausing there for questions

[pine tide]

oh yeah, this part is basically what I already know, from the video I watched. But basically nothing further, Kinda

[stark edge]

gotcha

so lets go through a hypothetical

[pine tide]

ok

[stark edge]

is "Fido" an acceptable name for a dog?

[pine tide]

I would think so

[stark edge]

okay, good

and we can make a dog named fido like this

Dog dog = new Dog();
dog.name = "Fido";

now

is "Sally" an acceptable name for a dog?

[pine tide]

I guess so too but I wouldnt name a dog that haha

[stark edge]

that was one of my dogs names so you take that shit back

you can make a dog named sally like this

Dog dog = new Dog();
dog.name = "Sally";

[pine tide]

haha sorry sorry

[stark edge]

okay now

[pine tide]

oh ok

[stark edge]

is "" an acceptable name for a dog?

[pine tide]

no

[stark edge]

but we can make a dog with no name like this

Dog dog = new Dog();
dog.name = "";

[pine tide]

what would that do

[stark edge]

just make a dog whose name is an empty string

we don't want that because we said "all dogs have a name"

[pine tide]

yeah

[stark edge]

and real quick, did you learn about null?

[pine tide]

no

[stark edge]

okay then we will ignore it

for now

[pine tide]

ok haha

[stark edge]

so thats the "problem" with fields

you can always set them to anything that is valid for the type

[pine tide]

oh ok

[stark edge]

if you have a String field, you can set it to any String

[pine tide]

I know what a String is but there is a more like specific definition to it. Like I know when to put it because I saw others do it but not necessarily the purpose

[stark edge]

Strings are text

[pine tide]

oh ok thats what I assumed but just needed to make sure

[stark edge]

https://javabook.net/strings

[pine tide]

so when it comes to public and private classes. what is the difference

or point of using one or the other

[stark edge]

well lets stick to fields for now

[pine tide]

ok

[stark edge]

if you have a field declared like this

class Dog {
    String name;
}

we call that "package-private"

that means that any code in "the same package" can access it

but code outside that package cannot

all java classes live in some package

like java.lang.String

the String class lives in the java.lang package

[pine tide]

so if you tried printing text outside of it, you counn't pull the string name from that class? (if my question makes sense)

[stark edge]

nah you can still access it from outside the class

just not outside the package

honestly, its hard to explain in full

but for all intents and purposes

[pine tide]

so vice versa wouldnt work

[stark edge]

class Dog {
    public String name;
}

class Dog {
    String name;
}

you can kindof think of these as "the same" while you are writing basic programs

[pine tide]

oh ok

[stark edge]

the whole public/private thing is useful for

1. "object design"
2. the design of larger programs

but okay

back to private

[pine tide]

ok

[stark edge]

one way to restrict people's ability to set a variable is to mark it private

class Dog {
    private String name;
}

[pine tide]

ohh

[stark edge]

this means that no code outside of the Dog.java file can set the field's value

or read its value

so if we wanted, now we can make restrictions like "dog names cannot be an empty string"

[pine tide]

so what I asked before, would that be true here with a private field? Outisde not accessing inside. Or are you getting at something else

[stark edge]

class Dog {
    private String name;

    void giveName(String newName) {
       if (newName.equals("")) {
           // crash
       }
       else {
           name = newName;
       }
    }
}

so if you tried printing text outside of it, you counn't pull the string name from that class? (if my question makes sense)
If you mean this

then yes

[pine tide]

yes

[stark edge]

with a private field you cannot pull the string name from the class

unless you are inside Dog.java

[pine tide]

ohh ok ok

[stark edge]

now, we answer a lot of student questions here, so my spider sense is tuned

so I can guess what your curriculum is going to try to show you next

[pine tide]

(I think I gotta switch professors, talking to a random guy on discord has been more helpfull in passed couple minutes then the passed 2 hours I spent reading these sentences he sent us over and over again haha)

and what is that?

[stark edge]

getters and setters

its...nonsense

obviously if you don't care about code just cheat and get the grade, fuck with circuits for the rest of your life or whatever

but otherwise, we generally point people here

https://java-programming.mooc.fi/

try going through this course to learn and answer questions on your assignments after

a random guy on discord
TBF you hit the jackpot

and i'm humble too

[pine tide]

I do care about coding and honestly find it super interesting. So Im trying to strain away from cheating and trying to understand what Im actually tying and doing so this helps alot

thank you lots man

or woman

but thanks alot

is this a course I have to pay for?

thats a dumb question ill just look hasha

[stark edge]

no it is not

[still trail]

Its free

[stark edge]

make other question threads for that

[pine tide]

for what

[stark edge]

people who are not me have gone through it here and can help you get set up

for asking more in depth questions about the mooc.fi course

[pine tide]

oh ok

[stark edge]

just keeps it tidy

[pine tide]

one more question, I think I know the answer to it but not too sure

oh actually nvm I think I got it

[stark edge]

k

[pine tide]

so defining a private field in a public class... inside the public class name, I write another line and just name it private before right? I need to do so with an integer

with how new I am, I dont know if my questions 100 percent make sense so if they dont then ill try and reword if I can

[pearl bolt]

u weite it in the class body which is inbetween the curly brace pair right after the class name