Understanding 2D Arrays in C Programming: Declaration, Initialization, and Manipulation

A 2D array, also known as a two-dimensional array, is a data structure in programming that stores values in a grid or matrix format with rows and columns. It is essentially an array of arrays, where each element of the outer array is itself an array that holds a fixed number of elements of the same data type. A 2D array is useful for storing and manipulating data that is arranged in a tabular format, such as a spreadsheet or a chessboard. Accessing elements in a 2D array requires specifying both the row and column index of the element.

• A sort of array known as a 2D array is capable of storing data in a structure resembling a table with rows and columns.
• Because it represents a mathematical value matrix, it is also known as a matrix.
• Two sets of square brackets, one for the rows and one for the columns, are used to declare 2D arrays.
• A 2D array has two indices: one for the row and one for the column, which may be used to retrieve its members.
• Data that is organised in a grid or table manner, such as photos, maps, and spreadsheets, can be stored in 2D arrays.
• They have a wide range of uses, including scientific calculations, image processing, and visual programming.
• Game boards and other visual elements can be represented using 2D arrays.

Syntax of 2D Arrays in C Programming

data_type array_name[row_size][column_size];

int myArray[3][4];

Here, data_type specifies the type of data that the array will hold, array_name is the name given to the array, row_size specifies the number of rows in the 2D array, and column_size specifies the number of columns in the 2D array.

For example, to declare a 2D integer array with 3 rows and 4 columns:

This creates a 2D array called myArray that can hold 3 rows and 4 columns of integers.

Example of 2D Arrays in C Programming

#include <stdio.h>

#define ROWS 3
#define COLS 4

int main() {
  int arr[ROWS][COLS];
  
  // Input values
  printf("Enter %d values for a %d x %d array:\n", ROWS*COLS, ROWS, COLS);
  for (int i = 0; i < ROWS; i++) {
    for (int j = 0; j < COLS; j++) {
      scanf("%d", &arr[i][j]);
    }
  }#include <stdio.h>

int main() {
    int rows, columns;

    printf("Enter the number of rows: ");
    scanf("%d", &rows);

    printf("Enter the number of columns: ");
    scanf("%d", &columns);

    int arr[rows][columns];

    printf("Enter the elements of the array:\n");

    // nested loop for input
    for(int i = 0; i < rows; i++) {
        for(int j = 0; j < columns; j++) {
            printf("arr[%d][%d]: ", i, j);
            scanf("%d", &arr[i][j]);
        }
    }

    printf("The elements of the array are:\n");

    // nested loop for output
    for(int i = 0; i < rows; i++) {
        for(int j = 0; j < columns; j++) {
            printf("%d ", arr[i][j]);
        }
        printf("\n");
    }

    return 0;
}

  
  // Output values
  printf("\nThe values you entered are:\n");
  for (int i = 0; i < ROWS; i++) {
    for (int j = 0; j < COLS; j++) {
      printf("%d ", arr[i][j]);
    }
    printf("\n");
  }
  
  return 0;
}

This program prompts the user to input the number of rows and columns for a 2D array. Then, it creates the array, receives user input using nested loops, and finally displays the array elements using another set of nested loops.

Output

Enter the number of rows: 3
Enter the number of columns: 2
Enter the elements of the array:
arr[0][0]: 1
arr[0][1]: 2
arr[1][0]: 3
arr[1][1]: 4
arr[2][0]: 5
arr[2][1]: 6
The elements of the array are:
1 2
3 4
5 6