CODEWITHSUNDEEP
javamultidimensional-arrayjava-2d
M Nasir Baloch
M Nasir Baloch

Reputation: 153

Initialization of 2D Array in Java?

I've a little confusion, when we declare & initialize a 2D array in java like given below

int arr[][]={{1,2,3,4},{4,3,2,1}};

This work correct, but when do do the above action like given below

int arr[2][4]={{1,2,3,4},{4,3,2,1}};

Then why it generates an error? Why can't we fix the size of rows and columns and then assign values in same statement? I know that we can do that separately using loops, something like arr[0][0]=345; and so on, but why can't we do it like this?

int arr[4][2]={{1,2,3,4},{4,3,2,1}};

Upvotes: 0

Views: 2025

Answers (1)

Auktis
Auktis

Reputation: 545

That’s because Java is not C language.
When you write int arr[][] = {{1, 2, 3, 4}, {4, 3, 2, 1}};, you declare and initialize a multidimensional array of 2 by 4. It is equivalent to the C language initialization you proposed (int arr[2][4] = {{1, 2, 3, 4}, {4, 3, 2, 1}};)

In Java, we preferably declare arrays in a Java-style manner:

int[][] arr = {{1, 2, 3, 4}, {4, 3, 2, 1}};

where int[][] is just a type identifier, we cannot specify size.
Moreover, in Java, we can initialize a 2D array that is not rectangular:

int[][] arr = {{1, 2, 3, 4}, {4, 3}};

If you want to declare an array of specific size, but don’t want to specify all it’s values at once, the only solution is to use new:

int[][] arr = new int[2][4];
arr[0][0] = 1;

Upvotes: 4

Related Questions