Droid project

Projects
1

im unable to understand why im getting error,

here is my code

public class Droid{
  //instance
  int batteryLevel;
  String name;
  
  public Droid(String droidName){
    //constructor
    name=droidName;
    batteryLevel=100;
  }
  
  
  public static void main(String[] args){
    Droid codey=new Droid("Codey"); 
    System.out.println(codey.droidName);
  }
}

and Error is
Droid.java:15: error: cannot find symbol
System.out.println(codey.droidName);
^
symbol: variable droidName
location: variable codey of type Droid
1 error

Link for Droid project

2

you have droidName here:

public Droid(String droidName)

as a parameter for the constructor, parameters have a local scope, so they only exist within that method. Which is why you get an error

you want to use the instance variable

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3

i’m quite confused too because in the instructions of “create a droid” it says that " Create a constructor method for the Droid class.

The method should have one parameter of String droidName ".so i followed the instructions even knowing droidName will be out of the main method’s Scope… they should fix instructions if they know that this will provide an error and a lot of confusions.

4

but if you look at the hint for step 7:

public class Person {

  int age;

  public Person(int yearsAlive) {
    age = yearsAlive;
  }

  public static void main(String[] args) {
    Person patrick = new Person(32);
    // printing the variable:
    System.out.println(patrick);
    // access the age field:
    System.out.println(patrick.age);
  }
}

you clearly see the instance variable/field is used.

learning the scope rules and OOP isn’t easy.

5

well for me it’s fun coding by following instructions and learning them hands on and not looking for hints that would give the answer right away…all i want is to have a clear and concise instructions since this is an e-learning site for newbie like me and it’s like the first rule in java iv’e read here in codeacademy. (to follow instructions correctly.)

6

but that is the problem, programming is everything except being provided with instructions

then the better question is: is java a suitable first language for you? Given its so OO without a way around it. Isn’t it better then to learn another language first?

7

Im stuck with step 13. with the method Energytransfer() . I still cant find the solution to it, do you have any idea of how to get this done.

8

Please see this topic:

How to ask good questions (and get good answers)

your reply is really difficult to understand what concepts and problems you are struggling with

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