Explain this code about Arrays

[Rashid Mian]

  int[] a = null ,  b [] = null;
b = a;
System.out.println( b );
 

Why above code gives comiplation error?

[Keith Lynn]

The line b[] = null doesn't make sense. You don't declare what b is, and you don't give a name to the array.

[Carol Enderlin]

C:\_tools\code>javac JRArray.java
JRArray.java:6: incompatible types
found   : int[]
required: int[][]
                 b = a;
                     ^

a and b aren't the same type, see the compilation error that I got

a is int[]
b is int[][]

[Anton Uwe]

b is a reference to a two-dimensional int array, a is a reference to a one-dimensional int array. You cannot assign a one-dim-array to a two-dim-array reference. So, "b=a" will raise a compile error.

[chintan ramavat]

You cannot do int i, j,k ; ===> ( int i, int j, int k)

i think your array B is not making any sense like is it integer or any reference variable.

int [] a ;
int [] b ; would be valid with valuse ==> NULL

[Jesse Custer]

The code you wrote is the same as this:

int[] a = null;
int[] b [] = null;
b = a;
System.out.println( b );

So now it's easier to see that a is a one-dime,sional array and b a 2-dimensional array. So Carol had it right.

Grtz


PS: In the K&B Book is stated that 'int[] a' is the same as 'int a[]'. This is not exactly correct. Although you will get the same result in this simple case, the difference is, that when you put the brackets before the name (next to the declared type), they will count for any variable you declare on that line. If you put the brackets after the name, they will only count for that specific variable.
[ February 15, 2007: Message edited by: Jesse Custer ]