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Hi all, i was just wondering with the below program what effect what
type casting have on the final output. I tried compiling the sample
below, but there were to many bugs in the program to get it to work. I
think that type casting would copy the value "cufflinks for Aus" into
T2, and it would be printed out twice. Can somebody verify this with
me.


public class Thingy
{
public TextField value;

public Object clone()
{
Thingy n;

n=new Thingy();
n.value=this.value;

return n;
}
}


------------------------------------------------------------------------------------------------------------------------------------------------
public class Question
{
Thingy t1,t2;

public static void main(String args[])
{

t1= new Thingy();

t1.value.setText("Cufflinks for Aus");

t2=(Thingy) t1.clone();
t2.value.setText("Bah Humbug!");
}


}

programming wrote:
> Hi all, i was just wondering with the below program what effect what
> type casting have on the final output. I tried compiling the sample
> below, but there were to many bugs in the program to get it to work. I
> think that type casting would copy the value "cufflinks for Aus" into
> T2, and it would be printed out twice. Can somebody verify this with
> me.
>
>
> public class Thingy
> {
> public TextField value;
>
> public Object clone()
> {
> Thingy n;
>
> n=new Thingy();
> n.value=this.value;
>
> return n;
> }
> }
>
>
> ------------------------------------------------------------------------------------------------------------------------------------------------
> public class Question
> {
> Thingy t1,t2;
>
> public static void main(String args[])
> {
>
> t1= new Thingy();
>
> t1.value.setText("Cufflinks for Aus");
>
> t2=(Thingy) t1.clone();
> t2.value.setText("Bah Humbug!");
> }
>
>
> }

Hmm, I think its time for you to get a Java book.

> programming wrote:
>> public class Thingy
>> {
>> public TextField value;

Most times one should keep member variables private and use accessor methods
to get at them.

>>
>> public Object clone()
Your intent is to override Object.clone(), correct?

>> {
>> Thingy n;
>>
>> n=new Thingy();
>> n.value=this.value;

This causes the clone to share a reference to the same TextField as its
progenitor's.

>>
>> return n;
>> }
>> }
>>
>>
>> ------------------------------------------------------------------------------------------------------------------------------------------------
>> public class Question
>> {
>> Thingy t1,t2;
>>
>> public static void main(String args[])
>> {
>>
>> t1= new Thingy();
>>
>> t1.value.setText("Cufflinks for Aus");
>>
>> t2=(Thingy) t1.clone();
>> t2.value.setText("Bah Humbug!");

This replaces the text attribute in the value field that is pointed to by both
t1 and t2.

>> }
>>
>>
>> }

Not only is the TextField 'value' shared, but it has public access, meaning
that it's subject to change any ol' which where.

- Lew