Mnozenie macierzy Matrix multiplication

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package mnozeniemaceirzy;



import static java.lang.System.*;
import java.util.Scanner;
import java.lang.ArrayIndexOutOfBoundsException;
/**
 *
 * @author Hylus
 */
public class Mnozeniemaceirzy {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {

        //Scanner input = new Scanner (System.in);
        double[][] mac1;
        double[][] mac2;
        double[][] mac3=null;
        out.printf ("Wprowadz pierwszy macierz:");
        mac1 = Wprowadz();
        out.printf ("Wprowadz 2 macierz:");
        mac2 = Wprowadz();
        try
        {
            mac3 = PomnozMacierz (mac1,mac2);
        }
        catch (Exception e)
        {
            out.printf ("macierze maja inny rozmair\n");
        }
        WyswietlMacierz (mac3);
        try
        {
            out.printf ("Transponuje macierz\n");
            mac3 = TransponujMacierz (mac3);
        }
        catch (ArrayIndexOutOfBoundsException e)
        {
            out.printf ("Ta macierz nie istnieje\n");
        }
        WyswietlMacierz (mac3);
    }


    public static double[][] Wprowadz()
    {
        double[][] mac;
        int x=0, y=0;
        Scanner input = new Scanner (System.in);
        out.printf ("Podaj rozmiar macierzu (y i x) \n");
        x = input.nextInt();
        y = input.nextInt();

        mac = new double [x][y];

        out.printf ("Wprowadz dane:\n");
        for (int i=0; i<x; i++)
        {
            for (int j=0; j<y ; j++)
            {
                out.printf ("[%d][%d] - ",i,j);
                mac[i][j] = input.nextDouble();
            }
        }

        return mac;
    }

    public static double[][] PomnozMacierz( double[][] mac1,double[][] mac2)
    {
        double[][] mac3;
        mac3 = new double [0][0];

        if (mac1.length == mac2[0].length)
        {
            mac3 = new double [mac1.length][mac2[0].length];

            for (int y=0 ; y < mac1.length; y++)
            {
                for (int x=0; x < mac2[0].length; x++)
                {
                    for (int i=0; i < mac1[0].length; i++)
                    {
                        mac3[y][x] = mac3[y][x] + mac1[y][i] * mac2[i][x];
                    }
                }
            }
        }
        else
        {
            out.printf ("macierze nie sa tych samych rozmairow\n");
        }

        return mac3;
    }

    public static void WyswietlMacierz (double[][] mac)
    {
        out.printf ("Wyswietlam wynik mnozenia macierzy\n");
        for (int i=0; i<mac.length; i++)
        {
            for (int j=0; j<mac[0].length ; j++)
            {
                out.printf ("%.2f ",mac[i][j]);
            }
            out.printf ("\n");
        }
    }

    public static double[][] TransponujMacierz (double[][] macierz)
    {
        double[][] macwyjsciowa;
        macwyjsciowa = new double[macierz[0].length][macierz.length];
        for (int y=0; y< macierz[0].length; y++)
        {
            for (int x=0; x < macierz.length; x++ )
            {
                macwyjsciowa[y][x] = macierz[x][y];
            }
        }
        return macwyjsciowa;
    }


}