❔ Matrix Multiplication

namespace SolH
{
    class H7
    {
        static int[,] MatrixMultiply(int[,] A, int[,] B)
        {
            int[,] R = new int[A.GetLength(0), B.GetLength(1)];

            for (int i = 0; i < A.GetLength(0); i++)
            {
                for (int j = 0; j < B.GetLength(1); j++)
                {
                    for (int k = 0; k < A.GetLength(1); k++) // why are we looping through A's columns?
                    {
                        R[i, j] = R[i, j] + A[i, k] * B[k, j]; //why do we need to add R[i, j]? Isnt it an empty array after we initialize it? 
                    }
                }
            }
            return R;
        }