Thread: About Array

Hello Experts!

I am new to this forum.
Could you please tell me how this multi-dimensional array works? How it corresponds to differents style of outputs format like triangle shape of elements output?

class TwoDAgain {
public static void main(String args[]) {
int twoD[][] = new int[4][];
twoD[0] = new int[1];
twoD[1] = new int[2];
twoD[2] = new int[3];
twoD[3] = new int[4];
int i, j, k = 0;
for(i=0; i<4; i++)
for(j=0; j<i+1; j++) {
twoD[i][j] = k;
k++;
}
for(i=0; i<4; i++) {
for(j=0; j<i+1; j++)
System.out.print(twoD[i][j] + " ");
System.out.println();
}
}
}

output:
0
1 2
3 4 5
6 7 8 9

Regards
Kaan

how this multi-dimensional array works

Multidim arrays are really a grouping of single dim arrays.
Each dim of the array can contain an array of a unique dimensions.

int twoD[][] = new int[4][];  // Create 2 dim array with 4 slots in the first dim
twoD[0] = new int[1];          //  set the first array to be a one dim array with 1 slot
twoD[1] = new int[2];          //  set the second array to be a one dim with 2 slots
twoD[2] = new int[3];         //  set the third array to be a one dim with 3 slots
twoD[3] = new int[4];         //  set the forth array to be a one dim with 4 slots

The valid indexes for the above array would be:
0,0
1,0 1,1
2,0 2,1 2,2
3,0 3,1 3,2 3,3