object declarations

[bucketbot]

just a quick questions that has been bugging me for a few days:

lets say i have some classes X and Y, and in some other part of the program, I make this declaration:

X xObject = new yObject();

What does that do?

thanks

[tmerkaj]

just a quick questions that has been bugging me for a few days:

lets say i have some classes X and Y, and in some other part of the program, I make this declaration:

X xObject = new yObject();

What does that do?

thanks

that does not work
but you can cast to do that
ex: X xObject =(X)( new yObject());

[tmerkaj]

that does not work
but you can cast to do that
ex: X xObject =(X)( new yObject());

of course if casting is allowed which will depend on the types of x and y

[r035198x]

just a quick questions that has been bugging me for a few days:

lets say i have some classes X and Y, and in some other part of the program, I make this declaration:

X xObject = new yObject();

What does that do?

thanks

You can do[CODE=java] List c = new ArrayList();[/CODE] .

Think about it and come up with the instances where it is allowed to do so. Don't forget to test for interfaces as well ...

[bucketbot]

ok, lets say its type casted. i dont understand what the xObject becomes if the yObject is stored into it.

thanks

[r035198x]

ok, lets say its type casted. i dont understand what the xObject becomes if the yObject is stored into it.

thanks

How about you think about this in terms reference types and what they are pointing to?


e.g
[CODE=java] X x = new Y();[/CODE]
The reference x of type X is pointing to an object of type Y.