array declaration

[Brian Spindler]

can someone explain why b gets a two dimensional declaration in this code:

public class TwoDimensionalArrayDeclaration {

	int[] foo = {1}, bar [] = {{2}, {3}};
	
	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// what this actually declares is that "b" is a 
		// two dimensional array
		int[] a = null, b [] = null;
		// and so this line fails to compile
		//a = b;
		
		TwoDimensionalArrayDeclaration tdat = new TwoDimensionalArrayDeclaration();
		
		System.out.println(tdat.foo + " : " + tdat.bar ); 

	}

}   
 

Nevermind foo and bar; they are my examples to prove the point visually.

[Duc Vo]

because (note the comma separator)

    int[] a = null, b [] = null;

is equivalent to

    int[] a = null;
    int[] b [] = null;

or

    int[] a = null;
    int[][] b = null;

[Ninad Kulkarni]

Also following code is

int a [] = null, b [] = null;

equivalent to

int [] a = null;
int [] b = null; 

and another way is

int a [] = null, b = 0;

is equivalent to

int [] a = null;
int b = 0;

[Arka Guhathakurta]

A few tips about array.....

  
int [] arr1,arr2;
  

The above code will declare two arrays of int primitive type.

 
int arr1[],arr2;
   

This code will declare an int array named arr1 and another int variable named arr2.
so if you write something like this...

  
int [] a,b[];
  

will probably declare a two dimensional array named b.

[Brian Spindler]

I think it's becoming much clearer now; it's really about the placement of the [] in regards to the association of the variable.

Thanks all!

[Shin Kudo]

[] when appears behind the type applies to all variables in this declaration,
[] when appears behind a variable only applies to that particular variable.

You can see example from Arka Guhathakurta's post.