CALCULATION OF ADDRESS IN 2D ARRAY
Date : 02.09.2012
Definition 2 D Array: A 2D array is an array in which each element is itself an Array.
For instance, an array A[M][N] is an M X N matrix.
Where : M = No. of rows
N = No. of Columns
M X N = No. of elements.
Implementation of 2-D Array : There are two way to store elements of 2-D array in Memory
1. Row Major - Where elements are stored row wise.
2. Column Major. Where elements are stored Column wise.
Finding The Location (address) of an element in 2-D array:
CASE : 1 . When elements are stored row wise:
Case 1.1 When lower bond is not given.
A[M][N] or A[M,N]
Address of A[I][J] or A[I,J] = B+ W[N( I)+J] .
M= Total No of Rows
N= Total No of Columns
I = Expected row
J = Expected Column
W = size of each element in byte.
Case 1.2 When lower bound is given.
A[Lr…Ur][Lc…Uc] or A[Lr : Ur , Lc : Uc]
Address of A[I][J] or A[I,J] = B+ W[N( I - Lr )+(J-Lc )] .
N= Uc – Lc + 1 (Total No of Columns )
I = Expected row
J = Expected Column
W = size of each element in byte.
Lr = Lower Bound of row
Lc= Lower Bound of column
Uc = Upper Bound of column
CASE : 2 . When elements are stored column wise:
Case 2.1 When lower bond is not given.
A[M][N] or A[M,N]
Address of A[I][J] or A[I,J] = B+ W[M(J)+I] .
M= Total No of Rows
N= Total No of Columns
I = Expected row
J = Expected Column
W = size of each element in byte.
Case 2.2 When lower bound is given.
A[Lr…Ur][Lc…Uc] or A[Lr : Ur , Lc : Uc]
Address of A[I][J] or A[I,J] = B+ W[( I - Lr )+M(J-Lc )] .
M= Uc – Lc + 1 (Total No of row)
I = Expected row
J = Expected Column
W = size of each element in byte.
Lr = Lower Bound of row
Lc = Lower Bound of column
Uc = Upper Bound of column
Basic Arithmetic Operation On 2 D Array.
-Addition
-Subtraction
-Multiplication
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