有两个矩阵a和b，均为2行3列。求两个矩阵之和。重载运算符“+”，使之能用于矩阵相加。如：c = a+b。

C++代码如下：

#include <iostream>
using namespace std;

class Matrix {
private:
    int mat[2][3];

public:
    Matrix() {}

    // 重载运算符+
    Matrix operator+(const Matrix &m) const {
        Matrix res;
        for (int i = 0; i < 2; i++) {
            for (int j = 0; j < 3; j++) {
                res.mat[i][j] = mat[i][j] + m.mat[i][j];
            }
        }
        return res;
    }

    // 重载运算符<<
    friend ostream& operator<<(ostream &os, const Matrix &m) {
        for (int i = 0; i < 2; i++) {
            for (int j = 0; j < 3; j++) {
                os << m.mat[i][j] << " ";
            }
            os << endl;
        }
        return os;
    }

    // 重载运算符>>
    friend istream& operator>>(istream &is, Matrix &m) {
        for (int i = 0; i < 2; i++) {
            for (int j = 0; j < 3; j++) {
                is >> m.mat[i][j];
            }
        }
        return is;
    }
};

int main() {
    Matrix a, b, c;
    cout << "请输入矩阵a：" << endl;
    cin >> a;
    cout << "请输入矩阵b：" << endl;
    cin >> b;
    c = a + b;
    cout << "a + b = " << endl;
    cout << c;
    return 0;
}

运行截图：