Java——矩阵类

Description

利用二维数组（double[]）实现一个矩阵类：Matrix。要求提供以下方法：
（1）set（int row, int col, double value）：将第row行第col列的元素赋值为value；
（2）get（int row，int col）：取第row行第col列的元素；
（3）width()：返回矩阵的列数；
（4）height()：返回矩阵的行数；
（5）Matrix add（Matrix b）：返回当前矩阵与矩阵b相加后的矩阵；
（6）Matrix multiply（Matrix b）：返回当前矩阵与矩阵b相乘后的矩阵。
（7）Matrix transpose()：返回当前矩阵的转置矩阵；
（8）toString()：以行和列的形式打印出当前矩阵。

Input

矩阵的行列数
矩阵的数据
设置矩阵值的行、列和值
获取矩阵值的行、列
待相加矩阵的行列数
待相加矩阵的值
待相乘矩阵的行列数
待相乘矩阵的值

Output

矩阵的行、列数
设置矩阵值后的矩阵
某行某列的矩阵值
矩阵相加结果
矩阵相乘结果
矩阵转置结果

Sample Input

3 3
1 2 3
4 5 6
7 8 9
2 3 8
1 3
3 3
1 2 3
4 5 6
7 8 9
3 2
1 2
1 2
1 2

Sample Output

row:3 column:3
after set value:
1 2 3
4 5 8
7 8 9
value on (1,3):3
after add:
2 4 6
8 10 14
14 16 18
after multiply:
6 12
17 34
24 48
after transpose:
1 4 7
2 5 8
3 8 9

import java.text.DecimalFormat;

import java.util.*;

class Matrix{

    private int row;//行

    private int col;//列

    //private double value;

    double [][]Data;

    

    public Matrix(int row, int col,double [][]Data) {

        this.row = row;

        this.col = col;

    //    this.value = value;

        this.Data = Data;

    }

    public void setMatrix(int row , int col, double value) {

        this.Data[row - 1][col - 1] = value;

    }

    public double getMatrix(int row, int col) {

        return Data[row - 1][col - 1] ;

    }

    public int width() {

        return row;

    }

    public int height() {

        return col;

    }

    public Matrix add(Matrix b) {

        if(this.width() != b.width() && this.height() != b.height()) {

            return null;

        }

        double add[][] = new double[this.row][this.col];

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

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

                add[i][j] = this.Data[i][j] + b.Data[i][j];

            }

        }

        Matrix another = new Matrix(this.col,this.row,add);    

        System.out.println("after add:");

        return another;

    }

    public Matrix multiply(Matrix b) {

        if(this.col != b.row) {

            return null;

        }

        double mul[][] = new double[this.row][b.col];

        double temp = 0;

        for(int i = 0;i<this.row;i++) {

            for(int k = 0;k<b.col;k++) {

                for(int j = 0;j<this.col;j++)

                    {

                    temp += this.Data[i][j] * b.Data[j][k];

                    }

                mul[i][k] = temp;

                temp = 0;

            }

        }

        Matrix another = new Matrix(this.row, b.col, mul);

        System.out.println("after multiply:");

        return another;

    }

    public Matrix transpose() {

        double tran[][] = new double[this.row][this.col];

        for(int i = 0;i<this.row;i++) {

            for(int j = 0;j<this.col;j++) {

                tran[j][i] = this.Data[i][j];

            }

        }

        Matrix another = new Matrix(this.col,this.row,tran);

        System.out.println("after transpose:");

        return another;

    }

    public String toString() {

        DecimalFormat df = new DecimalFormat("0");

        String result = "";

        //result += df.format(Data[0][0]);

        

        for(int i = 0;i<this.row;i++) {

            result += df.format(Data[i][0]);

            for(int j = 1;j<this.col;j++) {

                result += " " + df.format(Data[i][j]);

            }

            result +=  "\n";

        }

        return result;

    

    }

}

public class Main{

    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);

        int row = scan.nextInt();

        int col = scan.nextInt();

        System.out.println("row:" + row +" column:" + col);

        //set value

        double data[][] = new double[row][col];

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

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

                double d = scan.nextDouble();

                data[i][j] = d;

            }

        }

        Matrix matrix = new Matrix(row,col,data);

        int srow = scan.nextInt();

        int scol = scan.nextInt();

        double sv = scan.nextDouble();

        System.out.println("after set value:");

        matrix.setMatrix(srow, scol, sv);

        System.out.print(matrix);

        

        //get value

        DecimalFormat df = new DecimalFormat("0");

        int vrow = scan.nextInt();

        int vcol = scan.nextInt();

        System.out.print("value on (" +vrow + "," + vcol +"):");

        System.out.println(df.format(matrix.getMatrix(vrow, vcol)));

        //add

        int addrow = scan.nextInt();

        int addcol = scan.nextInt();

        double addMatrix[][] = new double[addrow][addcol];

        

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

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

                double ad = scan.nextDouble();

                addMatrix[i][j] = ad;

            }

        }

        Matrix add = new Matrix(addrow,addcol,addMatrix);

        System.out.print(matrix.add(add));

 

//        //mul

        int mulrow = scan.nextInt();

        int mulcol = scan.nextInt();

        double mulMatrix[][] = new double[mulrow][mulcol];    

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

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

                double mu = scan.nextDouble();

                mulMatrix[i][j] = mu;

            }

        }

        

         Matrix mul = new Matrix(mulrow,mulcol,mulMatrix);

         //System.out.print(matrix.add(add));

         System.out.print(matrix.multiply(mul));

        

         //transpose

         System.out.print(matrix.transpose());

 }

}