Lecture 23 Notes

multidimensional arrays in Java
--> array of arrays
--> Why? 
--> arrays are objects, so why not make the objects arrays....

declaration:
--> type[][].... each [] refers to a dimension

assignment
--> name = type[size1][size2]... 

but what about array of objects?
+ technically multidim array element is a reference to another object
+ the other object is an array

ex)  int[][] a = new int[2][3]
  
     means int[] a is first array of 2 elements
     that contain refs to 1-D arrays

     each of the 1-D arrays has 3 elements that can hold integers!

     (draw boxes here as column arrays)

       a        1st array          2nd arrays









     (draw in row major form)














AOA0 Example!

Ways to declare multidim arrays (because of aoa idea):
 int[][] x
 int[] x[] 
 int x[][]

Ragged arrays

Can leave out "furthest" size when creating arrays:
 int[][] x = new int[2][]
 Why?!?

 draw boxes










Row major vs col major