Can we access variables declared as private

[scracker]

Hi

Can we access private variables?

import java.awt.*;

public class Professors{
private String name;
private int age;

public Professors(String n, int a){
name = n;
age = a;
}

public boolean olderThan(Professors a){
return (age > a.age);
}
}

How come in this code we can do that? I remember my instructor said that to access a private instance variable, we need to write a get method to do that. Is that correct ? Thanks for answers.

[Philwx]

Private variables are accessible to the entire class they are made in.

They are for your class to use. When another class tries to access them it should not be able to. That class should have to access any data you are willing to give through public get and set methods. That is proper style anyway.

That way you control what can be accessed in your class. You can also make things "read only" by only supplying a "get" method but not a "set" method, for example. If they had direct access to your variables you would not be able to control this.

[cjard]

Originally posted by scracker
Hi

Can we access private variables?

only within the same set of curly brackets

import java.awt.*;

public class Professors{
 private String name;
 private int age;
 
 public Professors(String n, int a){
   name = n;
   age = a;
 }
 
 public boolean olderThan(Professors a){
   return (age > a.age);
 }
}

How come in this code we can do that?

access is based on classes, not objects. all object instances of Professors can access each others private variables. try this:

import java.awt.*;

public class Professors{
 private String name;
 private int age;

 public Professors(String n, int a){
   name = n;
   age = a;
 }

 public boolean olderThan(Professors a){
   return (age > a.age);
 }

 public static void main(String[] argv){
   Professors p1,p2;
   p1 = new Professors("bob", 10);
   p2 = new Professors("nob", 20);
   System.out.print(p1.olderThan(p2));
   System.out.print(p1.age);
 }

}
class test{

  int i;

  public test(Professors p){
    i = p.age;
  }
}

I remember my instructor said that to access a private instance variable, we need to write a get method to do that. Is that correct ?

yes, because it allows you to control the access to the data.. maybe the data is in some raw format and needs making nice before it is given out..