Multidimensional Array

Multidimensional Arrays

Multidimensional arrays are arrays of arrays are declared.

A simple example is given below for 2-D array:

int  int_array [ 10 ] [ 10 ] ;         //  A two dimensional array

• Initializing a two dimensional array

It can be initialized as follows :

int array [ 2 ] [ 2 ]  =  {1, 2, 3, 4}  ;

• Accessing the elements

Elements in two dimensional arrays can be accessed as follows:

a [ 0 ] [ 0 ]  =  10 ;    //  assigns 10 to element at first row first column

a [ 0 ] [ 1 ]  =  1 ;      //  assigns 1 to element at first row second column

a [ 2 ] [ 2 ]  =  11 ;    //  assigns 11 to element at third row third column

Implementation of a 2-D array

A two dimensional array can be implemented in a programming language in two ways :

1. Row major implementation

2. Column major implementation

Row major implementation

In it elements of array are read form keyboard row-wise i.e, complete first row is stored, then complete second row and so on.

Address of element,  a[i][j] = B + W ( n ( i – L₁ ) + ( j – L₂))

Where,       B     –     Base address

W    –     Size of each array element

n      –     Number of columns

L₁ –     Lower bound of row

L₂ –     Lower bound of column

Column major implementation

In it elements of array are read form keyboard column-wise i.e, complete first column is stored, then complete second column and so on.

Address of element,  a[i][j] = B + W ( m ( j – L₂ ) + ( i – L₁))

Where,

B     –     Base address

W    –     Size of each array element

m     –     Number of rows

L₁ –     Lower bound of row

L₂ –     Lower bound of column