Initialization

[sudha siva]

Hai,

public class Inst{
protected int mystate;
public void go(){
mystate=9;
System.out.print(mystate+" ");
}
public static void main(String args[]){
Inst a=new Inst();
a.go();
System.out.println(a.mystate);
}
}

IN the above code the output of a.mystate is 9. But I think it should be 0 because we assign the value 9 to the variable in the method go(),it is local to that variable. I'm confused of this initialization. Can anyone clear my doubt.

Thanks
sudha

[Vikrama Sanjeeva]

First of all clear one important point that mystate is not local variable, instead it is instance variable. That is every object/instance of Inst has it's own copy of mystate.
EXPLANATION:

public class Inst{
  protected int mystate; //Line 1
  public void go(){      //Line 2
    mystate=9;           //Line 3   
    System.out.print(mystate+" "); //Line 4
  }
  public static void main(String args[]){
    Inst a=new Inst();  //Line 5
    a.go();             //Line 6
    SysteM.out.println(a.mystate); //Line 7
  }
}

• At Line 1 instance variable has declared, mystateAt Line 5 Object of Inst has created, a.
  
• AT Line 6 go() is call.
  
• At Line 3 go() is assinged 9.Remember laste value of mystate was 0..Hence all instance varaible are assinged there default values just after the creation of object.That is just after execution of Constructor.
  
• At Line 4 mystate is printed as 9.Actually it is called at this Line by compiler as this.mystate.
  
• At Line 7 a.mystate is printed as 9.
  

Hope this helps.Any other quey is Wellcome.
Bye.
Viki.

------------------
Count the flowers of ur garden,NOT the leafs which falls away!
[This message has been edited by Vikrama Sanjeeva (edited November 20, 2001).]
[This message has been edited by Vikrama Sanjeeva (edited November 20, 2001).]

[Satya Prasad]

Hi Sudha,
u r confusing with local variable and instance vaiable.
when instance variable is declared , it is assigned a value 0 (if is in integer) , and u can access and change the value of this varaible any where in the code.
satya

Originally posted by sudha siva:
Hai,

public class Inst{
protected int mystate;
public void go(){
mystate=9;
System.out.print(mystate+" ");
}
public static void main(String args[]){
Inst a=new Inst();
a.go();
System.out.println(a.mystate);
}
}

IN the above code the output of a.mystate is 9. But I think it should be 0 because we assign the value 9 to the variable in the method go(),it is local to that variable. I'm confused of this initialization. Can anyone clear my doubt.

Thanks
sudha