Multidimensional Array in Data Structure - Learnengineeringforu

Multidimensional array

1. Array having more than one subscript variable is called multidimensional array.
2. Multidimensional array is also called as matrix.

Consider the Two dimensional array –

1. Two Dimensional Array requires Two Subscript Variables
2. Two Dimensional Array stores the values in the form of matrix.
3. One Subscript Variable denotes the “Row” of a matrix.
4. Another Subscript Variable denotes the “Column” of a matrix.

Declaration and Use of Two Dimensional Array :

int a[3][4];

Use :

for(i=0;i<row,i++)
   for(j=0;j<col,j++)
   {
   printf("%d",a[i][j]);
}

Meaning of Two Dimensional Array :

1. Matrix is having 3 rows ( i takes value from 0 to 2 )
2. Matrix is having 4 Columns ( j takes value from 0 to 3 )
3. Above Matrix 3×4 matrix will have 12 blocks having 3 rows & 4 columns.
4. Name of 2-D array is ‘a‘ and each block is identified by the row & column number.
5. Row number and Column Number Starts from 0.

Cell Location	Meaning
a[0][0]	0th Row and 0th Column
a[0][1]	0th Row and 1st Column
a[0][2]	0th Row and 2nd Column
a[0][3]	0th Row and 3rd Column
a[1][0]	1st Row and 0th Column
a[1][1]	1st Row and 1st Column
a[1][2]	1st Row and 2nd Column
a[1][3]	1st Row and 3rd Column
a[2][0]	2nd Row and 0th Column
a[2][1]	2nd Row and 1st Column
a[2][2]	2nd Row and 2nd Column
a[2][3]	2nd Row and 3rd Column

Two-Dimensional Array : Summary with Sample Example

Summary Point	Explanation
No of Subscript Variables Required	2
Declaration	a[3][4]
No of Rows	3
No of Columns	4
No of Cells	12
No of for loops required to iterate	2

Memory Representation

1. 2-D arrays are Stored in contiguous memory location row wise.
2. 3 X 3 Array is shown below in the first Diagram.
3. Consider 3×3 Array is stored in Contiguous memorylocation which starts from 4000 .
4. Array element a[0][0] will be stored at address 4000 again a[0][1] will be stored to next memory location i.e Elements stored row-wise
5. After Elements of First Row are stored in appropriate memory location , elements of next row get their corresponding mem. locations.

6. This is integer array so each element requires 2 bytes of memory.

Basic Memory Address Calculation :

a[0][1] = a[0][0] + Size of Data Type

Element	Memory Location
a[0][0]	4000
a[0][1]	4002
a[0][2]	4004
a[1][0]	4006
a[1][1]	4008
a[1][2]	4010
a[2][0]	4012
a[2][1]	4014
a[2][2]	4016

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