Assignments

[Galina Zapletnuka]

Exercise 7, Chapter 3, K&B book

I don't understand why this compiles:

1. class Zippy {
2. String[] x;
3. int[] a [] = {{1,2}, {1}};
4. Object c = new long[4];
5. Object[] d = x;
6. }

Can anyone explain lines 4&5 please? What does d refer to?

Thanks

[Alejandro Galvan]

Hi:

Arrays are always objects, whatever you store in the array (even primitive). That's why lines 4 and 5 compiles.

Hope this helps.

[Uttara Rishi]

Hi Galina,

String[] x;
Object[] d = x; // d =null

Can anyone explain lines 4&5 please? What does d refer to?

d refers to a 1- D String array .Remember since d is a 1 - D it can only refer to a 1-d array or anything that can be implictly cast like


dog d = new dog();
Object[] obj ;
obj = {new dog(),d}; // Since dog IS - A Object.Arrays make use of polymorphism.

Hope that helped.For a more thorough understanding check K & B book.

Uttara Rishi.
[ March 11, 2008: Message edited by: Uttara Rishi ]

[Galina Zapletnuka]

Thanks a lot, guys.
I'm primarily concerned about assigning an uninitialized variable (x) to another varaible (d) and what happens as a result.
I think I got it now