public class Matrix {
    private Object[][] matrix;
    private int height,width;//行，列
    Matrix(){}
    Matrix(int h,int w){
        height=h;//矩阵行数
        width=w;//矩阵列数
    }
    public void set(int row,int col,Object value)//将value插入row行，col列中
    {
        matrix=new Object[height][width];
        if(row>height||row<=0||col<=0||col>width)
        {
            System.out.println("此项不存在!");
        }
        matrix[row-1][col-1]=value;
    }
    public Object get(int row,int col)
    {
        return matrix[row-1][col-1];
    }
    public int width(){//返回矩阵的列
        return width;
    }
    public int height(){//返回矩阵的行
        return height;
    }
    public Matrix add(Matrix b)//矩阵相加
    {
        Matrix a=new Matrix();
        int i,j;
        if(height!=b.height()||width!=b.width())
        {
            return null;
        }
        else
        {
            for(i=0;i<height;i++)
            {
                for(j=0;j<width;j++)
                {
                    String m=matrix[i][j].toString();
                    String n=b.matrix[i][j].toString();
                    int value=Integer.parseInt(m)+Integer.parseInt(n);
                    a.set(i, j, value);
                }
            }
            return a;
        }
    }
    public Matrix multiply(Matrix b)
    {
        Matrix a=new Matrix();
        if(width!=b.height())
        {
            return null;
        }
        else
        {
            for(int i=0;i<height;i++)
            {
                for(int j=0;j<b.width();j++)
                {
                    int value=0;
                    for(int k=0;k<width;k++)
                    {
                        String m=matrix[i][k].toString();
                        String n=b.matrix[k][j].toString();
                        value+=Integer.parseInt(m)+Integer.parseInt(n);
                        a.set(i+1, j+1, value);
                    }
                }
            }
            return a;
        }
    }
    public void print() {// 打印出当前矩阵的值
        if(width!=0||height!=0){
            for (int i = 0; i < height; i++) {
                System.out.print("|\t");
                for (int j = 0; j < width; j++) {
                    System.out.print(matrix[i][j] + "\t");
                }
                System.out.print("|\n");
            }
        }
        else
        {
            System.out.println("该矩阵不存在。");
        }
    }
    public static void main(String[] args){
        Matrix a=new Matrix(2,2);
        a.set(1,1,1);
        a.set(1,2,2);
        a.set(2,1,3);
        a.set(2,2,4);
        a.print();
    }
}