Difference between int[] array and int array[]

Question

I have recently been thinking about the difference between the two ways of defining an array:

1. int[] array
2. int array[]
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Answer 1

While the int integers[] solution roots in the C language (and can be thus considered the "normal" approach), many people find int[] integers more logical as it disallows to create variables of different types (i.e. an int and an array) in one declaration (as opposed to the C-style declaration).

Answer 2

They're the same. One is more readable (to some) than the other.

Answer 3

From section 10.2 of the Java Language Specification:

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[][];

Personally almost all the Java code I've ever seen uses the first form, which makes more sense by keeping all the type information about the variable in one place. I wish the second form were disallowed, to be honest... but such is life...

Fortunately I don't think I've ever seen this (valid) code:

String[] rectangular[] = new String[10][10];

Answer 4

There is one slight difference, if you happen to declare more than one variable in the same declaration:

int[] a, b;  // Both a and b are arrays of type int
int c[], d;  // WARNING: c is an array, but d is just a regular int

Note that this is bad coding style, although the compiler will almost certainly catch your error the moment you try to use d.

Answer 5

Both are equally valid. The int puzzle[] form is however discouraged, the int[] puzzle is preferred according to the coding conventions. See also the official Java arrays tutorial:

Similarly, you can declare arrays of other types:

byte[] anArrayOfBytes;
short[] anArrayOfShorts;
long[] anArrayOfLongs;
float[] anArrayOfFloats;
double[] anArrayOfDoubles;
boolean[] anArrayOfBooleans;
char[] anArrayOfChars;
String[] anArrayOfStrings;

You can also place the square brackets after the array's name:

float anArrayOfFloats[]; // this form is discouraged

However, convention discourages this form; the brackets identify the array type and should appear with the type designation.

Note the last paragraph.

I recommend reading the official Sun/Oracle tutorials rather than some 3rd party ones. You would otherwise risk end up in learning bad practices.

Answer 6

It is an alternative form, which was borrowed from C, upon which java is based.

As a curiosity, there are three ways to define a valid main method in java:

• public static void main(String[] args)
• public static void main(String args[])
• public static void main(String... args)