C#: Multiplication of two square Matrices

C# Sharp Array: Exercise-21 with Solution

Write a C# Sharp program for multiplication of two square matrices.

Sample Solution:-

C# Sharp Code:

using System;

public class Exercise21  
{  
    public static void Main()
    {
        int i, j, k, r1, c1, r2, c2, sum = 0;

        int[,] arr1 = new int[50, 50]; // Declare the first matrix
        int[,] brr1 = new int[50, 50]; // Declare the second matrix
        int[,] crr1 = new int[50, 50]; // Declare the resultant matrix for multiplication

        // Display a message prompting the user to input the dimensions of the first matrix
        Console.Write("\n\nMultiplication of two Matrices\n");
        Console.Write("----------------------------------\n");  
        Console.Write("\nInput the number of rows and columns of the first matrix :\n");	
        Console.Write("Rows : ");
        r1 = Convert.ToInt32(Console.ReadLine());
        Console.Write("Columns : ");  
        c1 = Convert.ToInt32(Console.ReadLine());

        // Display a message prompting the user to input the dimensions of the second matrix
        Console.Write("\nInput the number of rows and columns of the second matrix :\n");  
        Console.Write("Rows : ");
        r2 = Convert.ToInt32(Console.ReadLine());
        Console.Write("Columns : ");   
        c2 = Convert.ToInt32(Console.ReadLine());  

        // Check if multiplication of matrices is possible
        if (c1 != r2)
        {
            Console.Write("Multiplication of matrices is not possible.");
            Console.Write("\nColumn of the first matrix and row of the second matrix must be the same.");
        }
        else
        {
            // Input elements into the first matrix
            Console.Write("Input elements in the first matrix :\n");
            for (i = 0; i < r1; i++)
            {
                for (j = 0; j < c1; j++)
                {
                    Console.Write("element - [{0}],[{1}] : ", i, j);
                    arr1[i, j] = Convert.ToInt32(Console.ReadLine());
                }
            }   

            // Input elements into the second matrix
            Console.Write("Input elements in the second matrix :\n");
            for (i = 0; i < r2; i++)
            {
                for (j = 0; j < c2; j++)
                {
                    Console.Write("element - [{0}],[{1}] : ", i, j);
                    brr1[i, j] = Convert.ToInt32(Console.ReadLine());
                }
            }    

            // Display the first matrix
            Console.Write("\nThe First matrix is :\n");
            for (i = 0; i < r1; i++)
            {
                Console.Write("\n");
                for (j = 0; j < c1; j++)
                    Console.Write("{0}\t", arr1[i, j]);
            }

            // Display the second matrix
            Console.Write("\nThe Second matrix is :\n");
            for (i = 0; i < r2; i++)
            {
                Console.Write("\n");
                for (j = 0; j < c2; j++)
                    Console.Write("{0}\t", brr1[i, j]);
            }

            // Matrix multiplication algorithm
            for (i = 0; i < r1; i++) // Row of the first matrix
            {
                for (j = 0; j < c2; j++) // Column of the second matrix
                {  
                    sum = 0;
                    for (k = 0; k < c1; k++)
                        sum = sum + arr1[i, k] * brr1[k, j];
                    crr1[i, j] = sum;
                }
            }

            // Display the resultant matrix after multiplication
            Console.Write("\nThe multiplication of two matrices is : \n");
            for (i = 0; i < r1; i++)
            {
                Console.Write("\n");
                for (j = 0; j < c2; j++)
                {
                    Console.Write("{0}\t", crr1[i, j]);
                }
            }
        }
        Console.Write("\n\n");
    }
}

Sample Output:

Multiplication of two Matrices                                                                                
----------------------------------                                                                            
Input the number of rows and columns of the first matrix :                                                    
Rows : 2                                                                                                      
Columns : 2                                                                                                   
Input the number of rows of the second matrix :                                                               
Rows : 2                                                                                                      
Columns : 2                                                                                                   
Input elements in the first matrix :                                                                          
element - [0],[0] : 1                                                                                         
element - [0],[1] : 2                                                                                         
element - [1],[0] : 3                                                                                         
element - [1],[1] : 4                                                                                         
Input elements in the second matrix :                                                                         
element - [0],[0] : 5                                                                                         
element - [0],[1] : 6                                                                                         
element - [1],[0] : 7
element - [1],[1] : 8                                                                                         
The First matrix is :                                                                                              
1       2                                                                                                     
3       4                                                                                                     
The Second matrix is :                                                                                        
5       6                                                                                                     
7       8                                                                                                     
The multiplication of two matrix is :                                                                         
19      22                                                                                                    
43      50                                                                                         

Flowchart:

C# Sharp Code Editor:

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