CODEWITHSUNDEEP
javaarraysfor-loop2d
userb
userb

Reputation: 173

Ragged 2D int array pyramid with Java

Write the code required to allocate a ragged 2-D int array such that the first row has space to store 1 value, the second row can store 2 values, the third row has space to store 3 values, etc. up until the 50th row which has space to store 50 values.

I know for the above question I have to essentially create a pyramid with a 2 dimensional array. I don't really know how to manipulate 2D arrays, any help will be great. This is my code thus far, not sure how to allocate space like the question above says:

import java.util.Arrays;
public class Ragged2D {

    public static void main(String[] args) {
        int[][] boo = new int[50][];


        for(int i = 0; i < boo.length; i++){

            for(int k = 0; k< boo[i].length; k++){

            }
        }
        System.out.println(Arrays.toString(boo));

    }
}

Upvotes: 2

Views: 2552

Answers (2)

Rafał Pydyniak
Rafał Pydyniak

Reputation: 539

I guess this is what you need

int[][] boo = new int[50][];

    for (int i=0;i<50;i++) {
        boo[i] = new int[i+1];
    }

This way boo[0] can contain 1 element (boo[0][0]), boo[1] can contain 2 elements (boo[0][0] and boo[0][1]) etc.

Upvotes: 1

Eran
Eran

Reputation: 393936

This is how you initialize a row of the 2D array:

public static void main(String[] args) {
    int[][] boo = new int[50][];


    for(int i = 0; i < boo.length; i++){
        boo[i] = new int[i+1]; // initialize the i'th row to have i+1 elements
        for(int k = 0; k< boo[i].length; k++){
            boo[i][k] = ...
        }
    }
    System.out.println(Arrays.deepToString(boo)); // this change is required to print 2D array
}

Upvotes: 1

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