How do we access elements from the two-dimensional array in C#?

A two-dimensional array in C# can be thought of as a table structure with rows and columns. Elements are accessed using two indices: the row index and the column index, separated by a comma within square brackets.

Syntax

Following is the syntax for accessing elements from a two-dimensional array −

dataType value = arrayName[rowIndex, columnIndex];

Following is the syntax for assigning values to elements −

arrayName[rowIndex, columnIndex] = value;

Accessing Individual Elements

Example

using System;

class Program {
   static void Main(string[] args) {
      // Declare and initialize 2D array
      int[,] numbers = { {1, 2, 3}, {4, 5, 6}, {7, 8, 9} };
      
      // Access specific elements
      Console.WriteLine("Element at [0,0]: " + numbers[0,0]);
      Console.WriteLine("Element at [1,2]: " + numbers[1,2]);
      Console.WriteLine("Element at [2,1]: " + numbers[2,1]);
      
      // Modify an element
      numbers[1,1] = 50;
      Console.WriteLine("Modified element at [1,1]: " + numbers[1,1]);
   }
}

The output of the above code is −

Element at [0,0]: 1
Element at [1,2]: 6
Element at [2,1]: 8
Modified element at [1,1]: 50

Accessing All Elements Using Loops

Example

using System;

class MyArray {
   static void Main(string[] args) {
      /* an array with 5 rows and 2 columns*/
      int[,] a = new int[5, 2] {{0,0}, {1,2}, {2,4}, {3,6}, {4,8} };
      int i, j;
      
      /* output each array element's value */
      for (i = 0; i < 5; i++) {
         for (j = 0; j < 2; j++) {
            Console.WriteLine("a[{0},{1}] = {2}", i, j, a[i,j]);
         }
      }
      
      // Access a specific element
      int x = a[1,1];
      Console.WriteLine("Specific element a[1,1] = " + x);
   }
}

The output of the above code is −

a[0,0] = 0
a[0,1] = 0
a[1,0] = 1
a[1,1] = 2
a[2,0] = 2
a[2,1] = 4
a[3,0] = 3
a[3,1] = 6
a[4,0] = 4
a[4,1] = 8
Specific element a[1,1] = 2

Using GetLength() Method

The GetLength() method returns the number of elements in a specific dimension, making loops more dynamic −

Example

using System;

class Program {
   static void Main(string[] args) {
      int[,] matrix = { {10, 20}, {30, 40}, {50, 60} };
      
      Console.WriteLine("Array dimensions: {0} rows, {1} columns", 
                        matrix.GetLength(0), matrix.GetLength(1));
      
      // Use GetLength() in loops
      for (int i = 0; i < matrix.GetLength(0); i++) {
         for (int j = 0; j < matrix.GetLength(1); j++) {
            Console.WriteLine("matrix[{0},{1}] = {2}", i, j, matrix[i,j]);
         }
      }
   }
}

The output of the above code is −

Array dimensions: 3 rows, 2 columns
matrix[0,0] = 10
matrix[0,1] = 20
matrix[1,0] = 30
matrix[1,1] = 40
matrix[2,0] = 50
matrix[2,1] = 60

Conclusion

Two-dimensional arrays in C# are accessed using row and column indices in the format array[row, column]. You can access individual elements directly or iterate through all elements using nested loops. The GetLength() method helps determine the dimensions dynamically for more flexible code.