When lower bond is not given.
The
computer keeps track of Base (BA),
the address of the first element A[0][0]
of A[M][N],
and computes address Loc (A[I][J]) of A[M][N] using the formula
Address can be calculated as Column major order:-
Loc
(A[I][J] ) = Base (BA) + W [M x J + I ]
Address can be calculated as Row major order:-
Loc (A
[I][J]) = Base (BA) + W [N x I + J ]
W denotes
the size, i.e; number of bytes per data element of the array A,
M is total
numbers of rows, and N is total number of columns in the array.
When lower bond is given.
Address can be
calculated as Row major order:-
Address of A[ I ][ J ]th element = BA + [ N * ( I - LBR) + ( J - LBC) ] * W
Where BA = Base address
W = Number of bytes occupied by each element
N = Number of columns
Address can be calculated as Column major order:-
Address of a[ I ][ J ]th element = BA + [ ( I - LBR) + M * ( J - LBC) ] * N
Where BA = Base address
W = Number of bytes occupied by each element
M = Number of rows
In case of C language
LBC (Lower bound column) = 0
e.g. Suppose element of array A[4][5] occupies 4 bytes, and the address of the 1st element is 49. Find the address of the element A(4,3) when the storage is row major.
= BA + [n * (i - LBR) + (j - LBC)] * w
= 49 + [5 * (4 – 0) + (3 - 0)] * 4
= 49 + [23] * 4
= 49 + 92
= 141
