C# Multidimensional array

In the previous chapter, we learned about C# arrays, how to initialize array and declare array in C#, now in this tutorial, we will see how to create multidimensional 2-D array in C#. We declare a one-dimensional array of integer numbers using int[], and we declare a two-dimensional with int[,]. For example :

int[,] twoDimensionalArray;

Above array has two dimensions, that is why it is called as 2 Dimensional array, while has it has more than one dimension, it is also called as multi-dimensional array in C#, these are also called as Matrices in mathematical term.

Similarly, we can declare three-dimensional array as

int[,,] threeDimensionalArray;

Syntax for declaring Multi-dimensional array in C#

dataType[,] variableName;         //  Two dimensional array
dataType[,,] variableName;       //   Three dimensional array

dataType[,] variableName = new dataType[size,size];            //  Three dimensional array
dataType[,,] variableName = new dataType[size,size,size];     //   Three dimensional array

Where,

datatype = can be any datatype, which will be stored in the array, can be int, string, char etc.

variableName = name of the array

size= size of row/column in an array

Multidimensional array declaration

We can declare multidimensional array in same way as we single dimension arrays, we just need to add comma (,) inside square brackets, for example

int[,] intMatrixArray; // for 2-d array, use one comma
string[,,] strCubeArray; // for 3-d array, using two comma

In the above examples, we have created two-dimensional int array and three-dimensional string array, each dimension is represented by comma(,).

We can allocate memory(size) of multidimensional array by using new keyword, as shown below

int[,] intMatrixArray = new int[3, 4]; 
string[,,] strCubeArray = new string[5, 5, 5];

In the above 2-D array, we are allocating size of 3 rows and 4 columns, take a look at the image below for understanding it

Multi-Dimensional Array Initialization

We can initialize 2-D array as shown below

int[,] matrix = {
    {0, 2, 4, 8}, // row 0 values
    {10, 12, 14, 16}, // row 1 values
};

int[,] array= new int[4,2] { 
                         { 1, 2 }, 
                         { 3, 4 },
                         { 5, 6 }, 
                         { 7, 8 }
                    };

for 3-D array, we can initialize it as shown below

int[,,] array= {
                {{12, 2, 8}},
                {{14, 5, 2}}, 
                {{3, 26, 9}},
                {{4, 11, 2}}
            };

Example of multi dimensional array in C#

Two dimensional array in C# example

using System;
					
public class Program
{
	public static void Main()
	{
		//two dimensional array declared and initiliazed
		int row=2;
		int columns=4;
		int[,] matrix = new int[2,4]{
					{0, 2, 4, 8}, // row 0 values
					{10, 12, 14, 16}, // row 1 values
				};

		    
           for (int i=0; i<row; i++) 
			{
				for (int j=0; j<columns; j++) 
				{
					Console.WriteLine(" Row "+i+ " , column "+j +" value ="+matrix[i, j]);
				} 
			}   
	}
}

Output

 Row 0 , column 0 value =0
 Row 0 , column 1 value =2
 Row 0 , column 2 value =4
 Row 0 , column 3 value =8
 Row 1 , column 0 value =10
 Row 1 , column 1 value =12
 Row 1 , column 2 value =14
 Row 1 , column 3 value =16

Three dimensional array example in C#

using System;
					
public class ThreeDimensionalArrayProgram
{
	public static void Main()
	{
		//three dimensional array
		int[,,] array= {
                {{12, 2, 8}},
                {{14, 5, 2}}, 
                {{3, 26, 9}},
                {{4, 11, 2}}
            };
		     //get array lengths
		    int d1 = array.GetLength(0); // array length at 1st dimension
            int d2 = array.GetLength(1); // array length at 2nd dimension
            int d3 = array.GetLength(2); // array length at 3rd dimension

		 
			    for (int i=0; i<d1; i++) 
				{
					for (int j=0; j<d2; j++) 
					{
						for (int k=0; k<d3; k++) 
						{
							Console.WriteLine(" value at position "+i+ " "+j+" "+k+ " ="+array[i, j, k]);
						} 
					} 
				}       

	
	}
}

output

value at position 0 0 0 =12
 value at position 0 0 1 =2
 value at position 0 0 2 =8
 value at position 1 0 0 =14
 value at position 1 0 1 =5
 value at position 1 0 2 =2
 value at position 2 0 0 =3
 value at position 2 0 1 =26
 value at position 2 0 2 =9
 value at position 3 0 0 =4
 value at position 3 0 1 =11
 value at position 3 0 2 =2

In the above code, we are using array.GetLength(Dimension) method, which gives us size of array, it is useful to get the number of elements in the specified dimension of the array.

Accessing Array Elements in MultiDimensional Array

We can directly access array element, by passing it's index, for two dimensional array, you need to pass two index's, first index = row and second index = column number, for example:

int[,] myArray = new int[3,2]{ 
                                {1, 2}, 
                                {3, 4}, 
                                {5, 6} 
                            };

myArray [0,0]; //Output: 1
myArray [0,1]; // 2

myArray [1,0]; // 3
myArray [1,1]; // 4

myArray [2,0]; // 5
myArray [2,1]; // 6

Similarly, for three dimensional array, you need to pass all three indexes locations

using System;
					
public class Program
{
	public static void Main()
	{
		int[,,] array= {
                {{12, 2, 8}},
                {{14, 5, 2}}, 
                {{3, 26, 9}},
                {{4, 11, 2}}
            };
		
		Console.WriteLine(array[0,0,0]); //outputs 12
		Console.WriteLine(array[0,0,1]); // outputs 2
		Console.WriteLine(array[0,0,2]); //outputs 8
		Console.WriteLine(array[1,0,0]);//outputs 14
	}
}

Output

Similarly, you are access all locations by passing indexes to an array.

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