设计一个2行3列的矩阵类，重载运算符"＋"和"-"，能实现矩阵类对象的加减运算；重载流插入运算符"<<“和流提取运算符”>>"，使之能用于矩阵的输入和输出。

好的，下面是一个简单的2行3列矩阵类的实现代码，包含了重载运算符和流插入/提取运算符：

#include <iostream>
using namespace std;

class Matrix {
public:
    Matrix() {}  // 默认构造函数
    Matrix(int m, int n) {  // 构造函数
        rows = m;
        cols = n;
        data = new int *[rows];
        for (int i = 0; i < rows; i++) {
            data[i] = new int[cols];
        }
    }
    ~Matrix() {  // 析构函数
        for (int i = 0; i < rows; i++) {
            delete[] data[i];
        }
        delete[] data;
    }

    // 重载运算符
    Matrix operator+(const Matrix& other) const {
        Matrix res(rows, cols);
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                res.data[i][j] = data[i][j] + other.data[i][j];
            }
        }
        return res;
    }

    Matrix operator-(const Matrix& other) const {
        Matrix res(rows, cols);
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                res.data[i][j] = data[i][j] - other.data[i][j];
            }
        }
        return res;
    }

    // 流插入/提取运算符
    friend ostream& operator<<(ostream& os, const Matrix& mat) {
        for (int i = 0; i < mat.rows; i++) {
            for (int j = 0; j < mat.cols; j++) {
                os << mat.data[i][j] << " ";
            }
            os << endl;
        }
        return os;
    }

    friend istream& operator>>(istream& is, Matrix& mat) {
        for (int i = 0; i < mat.rows; i++) {
            for (int j = 0; j < mat.cols; j++) {
                is >> mat.data[i][j];
            }
        }
        return is;
    }

private:
    int rows, cols;
    int **data;
};

int main() {
    Matrix mat1(2, 3), mat2(2, 3);

    // 输入矩阵 mat1 和 mat2
    cout << "Please input matrix mat1:" << endl;
    cin >> mat1;
    cout << "Please input matrix mat2:" << endl;
    cin >> mat2;

    // 输出矩阵 mat1 和 mat2
    cout << "mat1:" << endl;
    cout << mat1;
    cout << "mat2:" << endl;
    cout << mat2;

    // 矩阵加减
    cout << "mat1 + mat2:" << endl;
    cout << mat1 + mat2;
    cout << "mat1 - mat2:" << endl;
    cout << mat1 - mat2;

    return 0;
}

这段代码定义了一个 Matrix 类，包含了矩阵的行数和列数，以及矩阵元素的二维数组 data。重载了加减运算符以实现矩阵的加减运算，重载了流插入/提取运算符以实现矩阵的输入和输出。在 main 函数中，我们先输入两个矩阵 mat1 和 mat2，然后输出它们的和、差。