Is there a difference between
int[] array = new int[10];
and
int array[] = new int[10];
?
Both do work, and the result is exactly the same. Which one is quicker or better? Is there a style guide which recommends one?
-
2Official recommendation: the second notation is "Yechh": docs.oracle.com/javase/specs/jls/se7/html/…assylias– assylias2013-01-28 10:21:22 +00:00Commented Jan 28, 2013 at 10:21
-
@assylias I think the yechhh referred to doing int[] a[], instead of int[][] a. It's related, but not quite the same a what OP was asking about.Joshua Taylor– Joshua Taylor2017-11-14 16:43:00 +00:00Commented Nov 14, 2017 at 16:43
Add a comment
|
8 Answers
Both are equivalent. Take a look at the following:
int[] array;
// is equivalent to
int array[];
int var, array[];
// is equivalent to
int var;
int[] array;
int[] array1, array2[];
// is equivalent to
int[] array1;
int[][] array2;
public static int[] getArray()
{
// ..
}
// is equivalent to
public static int getArray()[]
{
// ..
}
1 Comment
But I'm Not A Wrapper Class
I personally think the flexibility using
[] can be confusing and should be more consistent (and strict).From JLS http://docs.oracle.com/javase/specs/jls/se5.0/html/arrays.html#10.2
Here are examples of declarations of array variables that do not create arrays:
int[ ] ai; // array of int
short[ ][ ] as; // array of array of short
Object[ ] ao, // array of Object
otherAo; // array of Object
Collection<?>[ ] ca; // array of Collection of unknown type
short s, // scalar short
aas[ ][ ]; // array of array of short
Here are some examples of declarations of array variables that create array objects:
Exception ae[ ] = new Exception[3];
Object aao[ ][ ] = new Exception[2][3];
int[ ] factorial = { 1, 1, 2, 6, 24, 120, 720, 5040 };
char ac[ ] = { 'n', 'o', 't', ' ', 'a', ' ',
'S', 't', 'r', 'i', 'n', 'g' };
String[ ] aas = { "array", "of", "String", };
The [ ] may appear as part of the type at the beginning of the declaration, or as part of the declarator for a particular variable, or both, as in this example:
byte[ ] rowvector, colvector, matrix[ ];
This declaration is equivalent to:
byte rowvector[ ], colvector[ ], matrix[ ][ ];
1 Comment
assylias
The latest version of the JLS is clearer on the subject: docs.oracle.com/javase/specs/jls/se7/html/…
They are both basically same, there is no difference in performance of any sort, the recommended one however is the first case as it is more readable.
int[] array = new int[10];
FROM JLS:
The [] may appear as part of the type at the beginning of the declaration, or as part of the declarator for a particular variable, or both.
1 Comment
karlihnos
It would be better if you extend the answer. Who recommends that? For me the second is more readable.
Both are the same.
I usually use int[] array = new int[10];, because of better (contiguous) readability of the type int[].
Comments
No, there is no difference. But I prefer using int[] array as it is more readable.
Comments
There is no difference between these two declarations, and both have the same performance.
Comments
There is virtually no difference.
answered Jan 28, 2013 at 10:15
Ivaylo Strandjev
71.4k18 gold badges130 silver badges183 bronze badges
Comments
In both examples, you are assigning a new int[10] to a reference variable.
Assigning to a reference variable either way will be equal in performance.
int[] array = new int[10];
The notation above is considered best practice for readability.
Cheers
