Multi-dimensional Array in C Programming

C programming language also support multidimensional arrays.

Syntax of multidimensional array declaration:

Data_type    array_name[size1][size2]…[sizeN];

For example, if we want to creates a three dimensional integer array −

int  num[5][10][4];

Two-dimensional Arrays

The simplest form of multidimensional array is the two-dimensional array.

if we want to declare a two dimensional integer array of size [x][y] ( where x is a  number of rows and y is a number of columns ) you would write something as follows −

 int  a[3][4];

In the above line we have created two-dimensional integer array ”a” with 3 rows and 4 columns.

In a C programming language Multidimensional arrays may be initialized by specifying bracketed values for each row.

For example we want to create an integer array with 3 rows and each row has 4 columns.

int a[3][4] = {  
                  { 1, 2, 3, 4 } ,   /*  for row index 0 */
                  { 5, 6, 7, 8 } ,   /*  for row index 1 */
                  { 9, 10, 11, 12}   /*  for row index 2 */
             };

Above the nested braces indicates the intended rows.

The following initialization is equivalent to the previous example −

int a[3][4] = {1,2,3,4,5,6,7,8,9,10,11,12};

which indicate the nested braces for intended row, are optional.

Accessing Elements of Two-Dimensional Array

Create a two-dimensional array of size 3*3 and  nested loop is used to handle a two-dimensional array −

#include 
 int main () 								
{

   /* an array with 3 rows and 3 columns*/
   int a[3][3] = { {1,2,3}, {4,5,6}, {7,8,9}};
   int i, j;
 
   /* output each array element's value */
   	for ( i = 0; i < 3; i++ ) 
	{
      		for ( j = 0; j < 3; j++ ) 
      		{
         			printf("a[%d][%d] = %d\n", i,j, a[i][j] );
      		}
   	}
   return 0;
}

a[0][0] = 1
a[0][1] = 2
a[0][2] = 3
a[1][0] = 4
a[1][1] = 5
a[1][2] = 6
a[2][0] = 7
a[2][1] = 8
a[2][2] = 9

Example: Write a program to create 3*3 matrix and take all elements of matrix as an input from user and print it.

#include 
 int main () 
{
   /* an array with 5 rows and 2 columns*/
   int a[3][3];
   int i, j;
	printf("Enter 9 elements of 3*3 matrix in sequence");
   	for ( i = 0; i < 3; i++ ) 	/* input each array element's value */
	{
		for ( j = 0; j < 3; j++ ) 
		{	scanf("%d", &a[i][j] );
      		}
   	}
 	printf("Elements of 3*3 matrix is \n");

   	/* output each array element's value */
   	for ( i = 0; i < 3; i++ ) 
	{
		for ( j = 0; j < 3; j++ ) 
		{
         			printf("%d ", a[i][j] );
      		}
      	printf("\n");
   	}
      return 0;
}

Enter 9 elements of 3*3 matrix in sequence
21 
32 
33 
44 
35 
23 
56 
45 
31
Elements of 3*3 matrix is 
21 32 33 
44 35 23 
56 45 31