JAVA 행렬 곱셈 결과

import java.util.Scanner;

 

public class ArrayTest4 {

   public static void main(String[] args) {

 

       int[][] matrix1 = { { 1, 2 }, { 3, 4 } };

       // [2][2]

       int[][] matrix2 = { { 3, 1 }, { 4, 2 } };

       int[][] matrix3 = matrixSum(matrix1, matrix2);

       int[][] matrix4 = matrixMul(matrix1, matrix2);

       // 행렬 합

 

       matrixPrint(matrix3);

       // 행렬 출력

   }

 

   private static int[][] matrixMul(int[][] matrix1, int[][] matrix2) {

       int[][] resultMatrix = new int[2][2];

 

       for (int j = 0; j < 2; j++) {

          for (int i = 0; i < 2; i++) {

            resultMatrix[j][i] = matrix1[j][0] * matrix2[0][i]

                    + matrix1[j][1] * matrix2[1][i];

          }

       }

 

       return resultMatrix;

   }

 

   private static void matrixPrint(int[][] matrix4) {

       for (int i = 0; i < 2; i++) {

          System.out.print("{");

          for (int j = 0; j < 2; j++) {

             System.out.print(" " + matrix4[i][j] + " ");

          }

          System.out.println("}");

       }

   }

 

   private static int[][] matrixSum(int[][] matrix1, int[][] matrix2) {

       int[][] resultMatrix = new int[2][2];

 

       for (int j = 0; j < 2; j++) {

          for (int i = 0; i < 2; i++) {

            resultMatrix[j][i] = matrix1[j][i] + matrix2[j][i];

          }

       }

 

       return resultMatrix;

   }

}