CODEWITHSUNDEEP
javaarraysconstructor
Master Maxx
Master Maxx

Reputation: 1

2D Array as a Class Variable

I am not able to understand why I have to mention the data type of the 2d array again and again if declared it as a class variable:

public class DDR
{
    int[][] arr; 
    int m;
    int n;
    public DDR() {
        m=0;
        n=0;
        int arr[][] = new int[m][n];
    }
}

When I omit int, it says "it's not a statement."

Upvotes: 0

Views: 413

Answers (2)

MAO3J1m0Op
MAO3J1m0Op

Reputation: 421

The int arr [] [] phrase in your constructor is actually declaring a new array that shadows your field. Remember that arrays are variables, too. Omitting the int makes a statement that syntactically makes no sense. In this case, what you want is to assign an array to your field arr of type int[][].

arr = new int[m][n];

Upvotes: 1

Mad Physicist
Mad Physicist

Reputation: 114230

Right now, arr in the constructor is not a class variable, but rather a local variable that is shadowing the class variable. Both int and [][] are part of the type.

To initialize the class variable, don't declare a new variable. You must omit both the element type (int) and the array portion of the declaration ([][]). Also, m and n have default values of zero, so you may want to set them before allocating the arrays:

m = 1;
n = 1;
arr = new int[m][n];

Upvotes: 2

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