C# – First steps with C# and .NET – part 045.

By | 03/10/2021
0 Comment

In this tutorial, I will show you how you can multiply two matrices using the C# programming language.
The full source code in C# can be found on my account on dotnetfiddle online tool.
This is the source code I used:

C#
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using System;
using System.Collections.Generic;
public class Program
{
public static void Main()
{
Console.WriteLine("Hello World");
 
int i,j,k;
int[,] A = {{1, 2}, {3, 5}, {1,1976}};
int[,] B = {{5, 10, 5}, {100, 1000, 1}};
var ARows = A.GetLength(0);  
var ACols = A.GetLength(1);  
var BRows = B.GetLength(0);  
var BCols = B.GetLength(1);
Console.WriteLine("Numebr of rows in matrix A:  " + ARows + " and number of columns in matrix A: " + ACols);
Console.WriteLine("Numebr of rows in matrix B:  " + BRows + " and number of columns in matrix B: " + BCols);
int[,] C = new int[ARows, BRows];
 
List<int> matrixDimA = new List<int>();
List<int> matrixDimB = new List<int>();
Console.WriteLine("Number of matrix A elements are :" + ARows *ACols);  
//matrixDimA.Reverse();
Console.WriteLine("Elements of matrix A elements are :");  
for (i = 0; i < ARows; i++)
{
Console.Write("[");
for (j = 0; j < ACols; j++)
{
if (j != ACols - 1)
{
Console.Write( A[i, j] + ",");
}
else
{
Console.Write( A[i, j]);
}
}
Console.WriteLine("]");
}
Console.WriteLine("Number of matrix A elements are :" + BRows *BCols);  
Console.WriteLine("Elements of matrix A elements are :");  
for (i = 0; i < BRows; i++)
{
Console.Write("[");
for (j = 0; j < BCols; j++)
{
if (j != BCols - 1)
{
Console.Write( B[i, j] + ",");
}
else
{
Console.Write( B[i, j]);
}
}
Console.WriteLine("]");
}
 
if((ARows == BCols) & (ACols == BRows))
{
Console.WriteLine("Matrix multiplication is possible because: ");
Console.WriteLine("Numebr of rows in matrix A:  " + ARows + " = with number of columns in matrix B: " + BCols);
Console.WriteLine("Numebr of columns in matrix A:  " + ACols + " = with number of rows in matrix B: " + BRows);
for (i = 0; i < ARows; i++)
{
Console.Write("[");
for (j = 0; j < BRows; j++)
{
if (j != ACols - 1)
{
C[i, j] = A[i, j] * B[j, i];
Console.Write( C[i, j] + ",");
}
else
{
C[i, j] = A[i, j] * B[j, i];
Console.Write( C[i, j]);
}
}
Console.WriteLine("]");
}
 
} else {
Console.WriteLine("Matrix multiplication rows is not possible.");
}
var CRows = C.GetLength(0);  
var CCols = C.GetLength(1);
Console.WriteLine("Number of matrix C elements are :" + CRows *CCols);  
Console.WriteLine("Elements of matrix C elements are :");  
 
for (i = 0; i < CRows; i++)
{
Console.Write("[");
for (j = 0; j < CCols; j++)
{
if (j != CCols - 1)
{
Console.Write( C[i, j] + ",");
}
else
{
Console.Write( C[i, j]);
}
}
Console.WriteLine("]");
}
}
}

This is the output:

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Hello World
Numebr of rows in matrix A:  3 and number of columns in matrix A: 2
Numebr of rows in matrix B:  2 and number of columns in matrix B: 3
Number of matrix A elements are :6
Elements of matrix A elements are :
[1,2]
[3,5]
[1,1976]
Number of matrix A elements are :6
Elements of matrix A elements are :
[5,10,5]
[100,1000,1]
Matrix multiplication is possible because:
Numebr of rows in matrix A:  3 = with number of columns in matrix B: 3
Numebr of columns in matrix A:  2 = with number of rows in matrix B: 2
[5,200]
[30,5000]
[5,1976]
Number of matrix C elements are :6
Elements of matrix C elements are :
[5,200]
[30,5000]
[5,1976]

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