inner class

[Teajl Shah]

Why "in.str" is giving error while the method which uses str variable compiles??
Tejal
public class outerdemo{
private int i=4;
private String str="JAVARANCH";
public static void main(String args[]){
outerdemo od=new outerdemo();
outerdemo.innerdemo in=od.new innerdemo();
System.out.println(in.addall());
//System.out.println(in.str);//gives compiler error:
in.printString();
System.out.println(od.str);
}//end main

private class innerdemo{
public int i=6;
int addall(){
int j=i++;
return j;
}//end addall
void printString(){
System.out.println(str);
}//end printstring
}//end inner

}//end outerdemo

[bill bozeman]

It is because when you say in.str you are return the variable str that is in reference object in, which is the inner class. Since in doesn't have a variable str you get an error.
However in the method printString in the innerclass, you are not saying this.str, you are just saying str. So it first looks to see if there is a varable local to the inner class, which there is not, so it looks to the outerclass next.
Try out different versions, make a str class in the innerclass, and it will work, change str to this.str in the printString method, and it will give you the variable not defined error, instead of printing in.str, print od.str and it will work.
Bill