totally cluless

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I was following some assistance that was provided by a codegym graduate person to a beginner and just stupidly copied and paste onto my assignment. I literally dont have a clue about whats going on i feel like the whole subject wasnt explained properly and I have 0 understanding of what is this code used to? what do we do here? what we assigning to what? like what are all of those className.variableName combinations? for now i do understand what a method is, what is a class and somewhat understand what is an object but i clearly can even recognize what is what in the code.. i can find the main method but to understand what an obejct is how to delcare it and what to assign to it? Feeling very very very stupid

package en.codegym.task.jdk13.task04.task0402; /* Price of apples */ public class Solution { public static void main(String[] args) { Apple apple = new Apple(); apple.addPrice(50); Apple apple2 = new Apple(); apple2.addPrice(100); System.out.println("Apple price " + Apple.applePrice); } public static class Apple { public static int applePrice = 0; public static void addPrice(int applePrice) { System.out.println("Parameter applePrice: " + applePrice); System.out.println("Class variable Apple.applePrice before addition: " + Apple.applePrice); Apple.applePrice = Apple.applePrice + applePrice; System.out.println("Class variable Apple.applePrice after addition: " + Apple.applePrice); } } }

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Thomas

Level 41 , Bayreuth, Germany

31 October, 09:15

There may be different kinds of variables inside a Java program. These tasks (and maybe a beginners book ;) ) will help you to see and understand that. Unfortunately there are hundreds of things that you need to know and when one tries to explain A, then B is necessary but you do not know about B yet. If I try to explain B then I need C for that and so on. What I mean is, that in the beginning you need to get rid of the urge to know everything right away. Be happy with the provided. If you do not understand something, step further. If it gets worse, step back a level and reread. Back to your question. There are different kinds of variables. Local variabels: That's variables defined inside a method. So every variable you declare inside the main method is a local variable. Method parameters, method arguments: Thats the same animal from a different perspective. If you declare a method, then you can also declare variables that can be passed to that method, like

public void myMethod(String s) { ...

String s would be the parameter. If you invoke that method and pass a value to that method then it is name 'method argument'. In the end it is like a local variable. Inside the method you can access s like if you declared it like a local var. Static or class variables: Now we're getting to the class and instance stuff. That needs time to understand and see the advantages. For now we ignore access modifiers like private. All the coming vars are public. A static variable belongs to the class level. Means everyone can access it from everywhere. You just write ClassName.variableName and you get its value. As easy as that. Instance variable (or field, attribute, object variable): This belongs to an instance of a class. Means you need to create an instance and only that instance has access to this variable. You can create more instances and all have it's own version of that variable with different values.

Thomas

Level 41 , Bayreuth, Germany

31 October, 09:24

Sometimes like in this task it may happen that there are instance or static variables that have the same name as a local variable. To show you that problem is the purpose of this task. To strip it down to the absolutely necessary we will have the following code:

public static class Apple {
    public static int applePrice = 0;

    public static void addPrice(int applePrice) {
        // what do we get here if we access applePrice
    }
}

We see a parameter appleName and a static variable appleName. So what will happen if you output applePrice inside the method addPrice. Java of course has rules for that. In that case the 'nearest' variable, the local variable or parameter will be used. If you intend to access the static (class) variable, you need to tell it the compiler with using it's 'full' name: Apple.applePrice, you write the class name followed by a dot and the name of the static variable. That's all ;) no magic.

LeonThePro

Level 4 , Israel

31 October, 14:11

thnkas! But to be honest i stepped back a bit and went to othe resources for now... i really feel like this is was over my head... I dont understand what this code supposed to do and how it works in general..

Thomas

Level 41 , Bayreuth, Germany

31 October, 16:42

The code does not much. As said it is hard to explain these things isolated of the rest that will follow. Later you will understand how the individual parts work together. But the lesson has to start somewhere.

David Richard

Level 17 , Palestine

1 November, 23:37

By (copy paste) ,basically that's no different than "skipping" tasks...aka you're not practicing, so I have to say...don't let your excitement get to your head and restart , pertend like you learnt nothing (because you really don't seem like learning) and go back to lesson zero , I know some tasks seems repetitive but that's for the best, don't skip any.... To sum it up : Saying "I got the hang of it, so I can skip this lesdon or that lesson is not important" this defeats the beautiful teaching system. When I came here, I had zero knoledge about programming, so my resolve was to not skip any little details, sometimes it's good, sometimes it's bad (espicially when the lesson itself tells you to not bother about certain detail that you would learn later) Hence , if you want to get the best results from this tewching program, follow the instructions as is....