Simple matrix multiplication sample - With jagged arrays replacing rectangular arrays

matrixmultiplication_jagged.cs

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*/

using System;

namespace matmuljagged
{
    class Program
    {
        const int rows = 10;
        const int columns = 10;

        static void Main(string[] args)
        {
            int[][] op1 = new int[rows][];
            int[][] op2 = new int[rows][];
            int[][] result = new int[rows][];

            for (var j = 0; j < rows; j++)
            {
                op1[j] = new int[columns];
                op2[j] = new int[columns];
                result[j] = new int[columns];
            }

            for (var i = 0; i < 2000000; i++)
            {
                Initialize(ref op1, ref op2);
                Multiply(op1, op2, ref result);
            }

            Console.WriteLine("\nOperand1:");
            Display(op1);

            Console.WriteLine("\nOperand2:");
            Display(op2);

            Console.WriteLine("\nResult:");
            Display(result);
        }

        static void Initialize(ref int[][] matrixA, ref int[][] matrixB)
        {
            Random rnd = new Random();

            for (var i = 0; i < rows; i++)
            {
                for (var j = 0; j < columns; j++)
                {
                    matrixA[i][j] = rnd.Next(0, 9);
                }
            }

            for (var i = 0; i < rows; i++)
            {
                for (var j = 0; j < columns; j++)
                {
                    matrixB[i][j] = rnd.Next(0, 9);
                }
            }
        }

        static void Multiply(int[][] matrixA, int[][] matrixB, ref int[][] matrixC)
        {
            for (var i = 0; i < rows; i++)
            {
                for (var j = 0; j < columns; j++)
                {
                    matrixC[i][j] = 0;
                    for (var inner = 0; inner < columns; inner++)
                    {
                        matrixC[i][j] += matrixA[i][inner] * matrixB[inner][j];
                    }
                }
            }
        }

        static void Display(int[][] sampleArray)
        {
            for (var i = 0; i < rows; i++)
            {
                for (var j = 0; j < columns; j++)
                {
                    Console.Write("{0, 5}  ", sampleArray[i][j]);
                }

                Console.WriteLine();
            }
        }
    }
}