matrix multiplication using C# and .NET

for (int i = 0; i < N; i++) {
    for (int j = 0; j < N; j++) {
        for (int k = 0; k < N; k++) {
            C[i,j] += A[i,k] * B[k,j];
        }
    }
}

using System;

class Program
{
static void Main(string[] args)
{
Console.WriteLine("Enter the number of rows and columns");
int r = int.Parse(Console.ReadLine());
int c = int.Parse(Console.ReadLine());
int[,] a = new int[r, c];
int[,] b = new int[r, c];
int[,] res = new int[r, c];
Console.WriteLine("Enter the elments to first matrix");
for (int i = 0; i < r; i++)
{
string[] s = Console.ReadLine().Split(' ');
for (int j = 0; j < c; j++)
{
a[i, j] = int.Parse(s[j]);
}
}

Console.WriteLine("the elements of first matrix are");
for (int i = 0; i < r; i++)
{
for (int j = 0; j < c; j++)
{
Console.Write(a[i, j] + " ");
}
}
Console.WriteLine("");
Console.WriteLine("Enter the elements to second matrix");
for (int i = 0; i < r; i++)
{
string[] s1 = Console.ReadLine().Split(' ');
for (int j = 0; j < c; j++)
{
b[i, j] = int.Parse(s1[j]);
}
}
Console.WriteLine("the elements of second matrix are");
for (int i = 0; i < r; i++)
{
for (int j = 0; j < c; j++)
{
Console.Write(b[i, j] + " ");
}
}

for (int i = 0; i < r; i++)
{

for (int j = 0; j < c; j++)
{
res[i, j] = 0;
for (int k = 0; k < r; k++)
{
res[i, j] += a[i, k] * b[k, j];
}

}
}
Console.WriteLine("\nThe Matrix Multiplication is");
for (int i = 0; i < r; i++)
{
Console.WriteLine("");
for (int j = 0; j < c; j++)
{
Console.Write(res[i, j]+" ");
}
}
Console.ReadLine();

}
}