in multidimensional array what is the row and coloumn size.for example in 2d array a[2][2] this has 2 rows and 2coloumns .but what does this have a[2][3][4]????please explain me with practical example

a[2][3][4] is a 3 dimensional array
that has an array of 2 elements where each element is an array of 3 elements where each element is an array of 4 elements.

though its old, you can check this article for an example
try searching through google for more examples and related info

are'nt they using 3d arrays now???

elements are ok??what is coloumn and row size?

rows and columns are just common interpretations for 2d arrays
I think its more correct to think of it as arrays of arrays or elements of the elements and so on