// 2020/4/22(水)～26(日)

import java.io.*;
import java.util.Scanner;

public class Gyoretsu6 {
    public static void main(String[] args) {
        System.out.println("2つの行列の積を求めます");

        System.out.println("\n行列Aを入力します");
        double[][] matrixA;
        if ((args.length == 3 || args.length == 6) && args[0].equals("-i")) {
            matrixA = readFile(args[1]);
        } else if (args.length == 6 && args[3].equals("-i")) {
            matrixA = readFile(args[4]);
        } else {
            matrixA = inputMatrix();
        }
        System.out.println("行列Aを出力します");
        printMatrix(matrixA);

        System.out.println("\n行列Bを入力します");
        double[][] matrixB;
        if ((args.length == 3 || args.length == 6) && args[0].equals("-i")) {
            matrixB = readFile(args[2]);
        } else if (args.length == 6 && args[3].equals("-i")) {
            matrixB = readFile(args[5]);
        } else {
            matrixB = inputMatrix();
        }
        System.out.println("行列Bを出力します");
        printMatrix(matrixB);

        System.out.println("\n積ABを計算します");
        double[][] matrixAB = multiplyMatrix(matrixA, matrixB);
        System.out.println("積ABを出力します");
        printMatrix(matrixAB);
        if ((args.length == 3 || args.length == 6) && args[0].equals("-o")) {
            writeFile(args[1], matrixAB);
        } else if (args.length == 6 && args[3].equals("-o")) {
            writeFile(args[4], matrixAB);
        } else {
            return;
        }

        System.out.println("\n積BAを計算します");
        double[][] matrixBA = multiplyMatrix(matrixB, matrixA);
        System.out.println("積BAを出力します");
        printMatrix(matrixBA);
        if ((args.length == 3 || args.length == 6) && args[0].equals("-o")) {
            writeFile(args[2], matrixBA);
        } else if (args.length == 6 && args[3].equals("-o")) {
            writeFile(args[5], matrixBA);
        } else {
            return;
        }
    }

    public static double[][] inputMatrix() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("行列の行の大きさを自然数で入力して下さい");
        int row = scanner.nextInt();
        System.out.println("行列の列の大きさを自然数で入力して下さい");
        int column = scanner.nextInt();
        double[][] matrix = new double[row][column];
        for (int i = 0; i < row; i++) {
            for (int j = 0; j < column; j++) {
                System.out.println("行列の" + (i + 1) + "行" + (j + 1) + "列の要素の値(実数)を入力して下さい");
                matrix[i][j] = scanner.nextDouble();
            }
        }
        return matrix;
    }

    public static void printMatrix(double[][] matrix) {
        if (matrix == null) {
            System.out.println("表示はありません");
            return;
        }
        for (int i = 0; i < matrix.length; i++) {
            for (int j = 0; j < matrix[0].length; j++) {
                System.out.print(matrix[i][j] + " ");
            }
            System.out.println();
        }
    }

    public static double[][] multiplyMatrix(double[][] matrix1, double[][] matrix2) {
        if (matrix1[0].length != matrix2.length) {
            System.out.println("この2つの行列はこの順では積が求められません");
            return null;
        }
        double[][] product = new double[matrix1.length][matrix2[0].length];
        for (int i = 0; i < matrix1.length; i++) {
            for (int j = 0; j < matrix2[0].length; j++) {
                for (int k = 0; k < matrix1[0].length /* matrix2.lengthでも同じ */ ; k++) {
                    product[i][j] += matrix1[i][k] * matrix2[k][j];
                }
            }
        }
        return product;
    }

    public static double[][] readFile(String fileName) {
        String line = null;
        int lineCount = 0;
        String[] lineArray = null;
        try(FileReader fr = new FileReader(fileName);    /* FileNotFoundException */
        BufferedReader br = new BufferedReader(fr);) {
            while((line = br.readLine()) != null) {    // IOException
                if (lineCount == 0) {
                    lineArray = line.split("[ ]");
                }
                lineCount++;
            }
        } catch(FileNotFoundException e1) {
            e1.printStackTrace();
        } catch(IOException e2) {
            e2.printStackTrace();
        }
        double[][] matrix = new double[lineArray.length][lineCount];

        line = null;
        int lineNum = 0;
        String[][] lineTable = new String[lineArray.length][lineCount];
        try(FileReader fr = new FileReader(fileName);
        BufferedReader br = new BufferedReader(fr);) {
            while((line = br.readLine()) != null) {
                lineTable[lineNum] = line.split("[ ]");
                lineNum++;
            }
        } catch(FileNotFoundException e1) {
            e1.printStackTrace();
        } catch(IOException e2) {
            e2.printStackTrace();
        }
        for (int i = 0; i < lineArray.length; i++) {
            for (int j = 0; j < lineCount; j++) {
                matrix[i][j] = Double.parseDouble(lineTable[i][j]);
            }
        }
        System.out.println("ファイル" + fileName + "から読み込みました");
        return matrix;
    }

    public static void writeFile(String fileName, double[][] matrix) {
        if (matrix == null) {
            System.out.println("書き込みはありません");
            return;
        }
        try(FileWriter fw = new FileWriter(fileName);) {    // ファイル上書き
            for (int i = 0; i < matrix.length; i++) {
                for (int j = 0; j < matrix[0].length; j++) {
                    fw.write(matrix[i][j] + " ");
                }
                fw.write("\n");
            }
            fw.flush();
        } catch(IOException e) {
            e.printStackTrace();
        }
        System.out.println("ファイル" + fileName + "に書き込みました");
    }
}