Multi dimansional Array,Master Exam

[Mushraf Khan]

GoodDay EveryOne

This is from Master Exam A ,
Can anyone please clear the the below query. I tried to read some of the post based on this question, got more confused. Can anyone please help me with my below quoted queries. i would really apprecaite. I really need your great help to make this cleared.

A,B,E,F are correct.

public class Test{
public static void main(String args[])
{
short [][]b  new short[4][4];
short [][] big = new short[2][2];
short b3=8;
short b2[][][][] = new short[2][3][2][2];
//insert code here
} }

A. b2[1][1] = big;----- I guess there are 4 arrays in b2, what does b2[1][1] mean
B b[1][]0] = b3; --- second array, O th element , means second array of b, value of element at index 0 . is this correct
C b2[0][1][1] = b ----- Couldnt figure how b2[0][2][1] has come
D b2[0][2][1] = b[1][0]---- Couldnt figure how this came
E b2[1][1][0][1] = b[1][0] -----Couldnt figure how this came
F b2[1][1] = b ------Couldnt figure how this came

[John Jai]

I have the answers as comments in the below program.

public class MultiArrays {
	public static void main(String...args){
		short[][] b = new short[4][4]; 
		short[][] big = new short[2][2]; 
		short     b3 = 8; 
		short[][][][] b2 = new short[2][3][2][2]; 
 
		// big is a two-dimensional array.
		// b2 is a four dimensional array
		// b2[][] - is actually a two dimensional array that has another 2 two dimensional array that makes it b2[][][][]
		b2[1][1] = big;
		
		// b3 is just a short primitive that is assigned to 0'th position of the b[1] array
		b[1][0] = b3;

		// The position z in b2[x][y][z] can hold a single dimension array. Not a two dimension array		
		b2[0][1][1] = b;
		
		// Above said that the position y in b2[x][y] can hold a two dimension array.
		// Hence below will compile
		b2[0][1] = b;
		
		// Same below - A single dimension array is expected at position z in b2[x][y][z]. But you give a primitive short and not 
		// a single dimension array that holds short
		b2[0][2][1] = b[1][0];
		
		// Having said that, the position D in b2[A][B][C][D] can hold a short... So below will compile
		b2[0][2][1][0] = b[1][0];
		
		// Similar one is the E option
		b2[1][1][0][1] = b[1][0];
		
		// By this time you should tell how this is valid!
		b2[1][1] = b;
	}
}

[Mushraf Khan]

Thanks a lot John. Had always the problem of arrays when it was more than one dimensional. The explaination was crystal clear. Earlier i used to count dont know what in the [] and tried to figure out some logic. This was really clear. Sorry for the late reply , been bit busy with my kids activities.
Thanks again.


Regards
Mushraf Khan

[Ankit Garg]

As John explained already you should think of two dimensional arrays as array of arrays, you can read a tutorial like this on this. That is the only reason why its possible to have a two dimensional array with each 'row' having different number of 'columns'...

[Mushraf Khan]

Thanks a Lot, Ankit Garg. It was really useful information. Broadened my knoweldge about Arrays and best of all understood it. Thanks again.