Multi-Dimensional Array in C

Multi-Dimensional Array in C

In this article, I am going to discuss the Multi-Dimensional Array in C with Examples. Please read our previous articles, where we discussed One Dimensional Array in C Language.

Multi-Dimensional Array in C:

An array of arrays is called a multi-dimensional array. In simple words, an array created with more than one dimension (size) is called a multi-dimensional array. The multi-dimensional array can be of a two-dimensional array or three-dimensional array or four-dimensional array or more. 

Syntax: type name[size1][size2]…[sizeN];
Example: int a[3][3][3];

Program:
#include <stdio.h>
void arr(int x[][3]);  //function prototype
int main ()
{
   int a[2][3] = {{1,2,3}, {4,5,6}};   //initializing array
   int b[2][3] = {1, 2, 3, 4, 5};
   int c[2][3] = {{1, 2}, {4}};
   printf("values in array a by row:\n");
   arr(a);
   printf("values in array b by row:\n");
   arr(b);
   printf("values in array c by row:\n");
   arr(c);
   return 0;
}             // end of main
void arr(int x[][3])
{
   int i;      //row counter
   int j;      //column counter
   for (i = 0; i <= 1; ++i)
   {
      for (j = 0; j<= 2; ++j)
      {
         printf("%d", x[i][j]);
      }       //end of inner for
      printf("\n");
   }          //end of outer for
}

Output:

Multi-dimensional Array in C

The most popular and commonly used multi-dimensional array is two-dimensional array. The 2-D arrays are used to store data in the form of a table. We also use 2-D arrays to create mathematical matrices.

Two-Dimensional Array in C:

The Two-dimensional array is nothing but a table with rows and columns. A two-dimensional array can be expressed as a contiguous and tabular block in memory where the data can be stored in table structure.

Declaration of Two-Dimensional Array
Syntax: datatype arrayName [ rowSize ] [ columnSize ];

Initialization of Two-Dimensional Array
Syntax: datatype arrayName [rows][colmns] = {{r1c1value, r1c2value, …},{r2c1, r2c2,…}…};

Example: int matrix_A [2][3] = { {1, 2, 3},{4, 5, 6} };

The above declaration of two-dimensional array reserves 6 contiguous memory locations of 2 bytes each in the form of 2 rows and 3 columns. And the first row is initialized with values 1, 2 & 3 and the second row is initialized with values 4, 5 & 6. We can also initialize as follows:

Multi-Dimensional Array in C

Accessing Individual Elements of Two-Dimensional Array

To access elements of a two-dimensional array we use array name with row index value and column index value of the element that to be accessed. Here the row and column index values must be in separate square braces. In the case of the two-dimensional array, the compiler assigns separate index values for rows and columns.

Syntax: arrayName [ rowIndex ] [ columnIndex ];
Example: a[0][1] = 20;
Here, the element with row index 0 and column index 1 of ‘a’ array is assigned with value 10.

Implementation of Two-Dimensional Array in C:

A two-dimensional array can be implemented in two ways:

  1. Row major implementation
  2. Column major implementation
#include <stdio.h>
#define ROW_SIZE 4 // Define constant row size
#define COL_SIZE 3 // Define constant column size
int main()
{
    int matrix[ROW_SIZE][COL_SIZE];
    int row, col;
    printf("Enter elements in matrix of size %dx%d \n", ROW_SIZE, COL_SIZE);
    /* Outer loop to iterate through each row */
    for(row=0; row<ROW_SIZE; row++)
    {
        /* Inner loop to iterate through columns of each row */
        for(col=0; col<COL_SIZE; col++)
        {
            /* Input element in array */
            scanf("%d", &matrix[row][col]);
        }
    }
    /* Print all elements of array */
    printf("\nElements in matrix are: \n");
    for(row=0; row<ROW_SIZE; row++)
    {
        for(col=0; col<COL_SIZE; col++)
        {
            printf("%d ", matrix[row][col]);
        }
        printf("\n");
    }
    return 0;
}

Output:

Program for Two-Dimensional Array in C

Points to Remember:
  1. In 2d array elements are arranged in rows and columns format.
  2. When we are working with the 2D array we require to use 2 subscript operators which indicates the row and column sizes.
  3. In 2D array when we are referring one subscript operator then it gives rows address, 2nd subscript operator gives the element
  4. The main memory of the 2D array is rows and sub-memory is columns.
  5. On the 2D array, the array name always gives the main memory that is 1st-row base address, arr+1 will give the next row base address.
Program for 3-D Array:
#include <stdio.h>
#define SIZE1 2
#define SIZE2 2
#define SIZE3 3
int main()
{
    int arr[SIZE1][SIZE2][SIZE3];
    int i, j, k;
    /*Input elements in array*/
    printf("Enter elements in three-dimensional array of size %dx%dx%d \n", SIZE1, SIZE2, SIZE3);
    for(i = 0; i < SIZE1; i++)
    {
        for(j = 0; j < SIZE2; j++)
        {
        	for (k = 0; k < SIZE3; k++)
        	{
            	scanf("%d", &arr[i][j][k]);	
        	}
        }
    }
    /*Print elements of array*/
    printf("\nElements in three-dimensional array are: \n");
    for(i = 0; i < SIZE1; i++)
    {
        for(j = 0; j < SIZE2; j++)
        {
        	for (k = 0; k < SIZE3; k++)
        	{
            	printf("%d\n", arr[i][j][k]);	
        	}
        }
    }
    return 0;
}

Output:

Program for 3-D Array

Applications of Arrays in C

In C Programming language, arrays are used in a wide range of applications. A few of them are as follows…

Arrays are used to Store List of values: In C Programming language, single-dimensional arrays are used to store a list of values of the same datatype. In other words, single-dimensional arrays are used to store a row of values. In single dimensional array data is stored in linear form.

Arrays are used to Perform Matrix Operations: We use two-dimensional arrays to create matrix. We can perform various operations on matrices using two-dimensional arrays.

Arrays are used to implement Search Algorithms: We use single-dimensional arrays to implement search algorithms like Linear Search, Binary Search

Arrays are used to implement Sorting Algorithms: We use single-dimensional arrays to implement sorting algorithms like Insertion Sort, Bubble Sort, Selection Sort, Quick Sort, Merge Sort, etc.,

Arrays are used to implement Data structures: We use single-dimensional arrays to implement data structures like Stack Using Arrays and Queue Using Arrays

In the next article, I am going to discuss Functions using Array in C with examples. Here, in this article, I try to explain the Multi-Dimensional Array in C Langauge. I hope you enjoy this Multi-Dimensional Array in C Program article. I would like to have your feedback. Please post your feedback, question, or comments about this article

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