c++定义一个矩阵类代码

下面是一个简单的矩阵类的 C++ 代码示例：

#include <iostream>
#include <vector>

class Matrix {
private:
    int rows, cols;
    std::vector<std::vector<int>> data;
public:
    Matrix(int r, int c) : rows(r), cols(c), data(std::vector<std::vector<int>>(r, std::vector<int>(c))) {}

    int getRows() const {
        return rows;
    }

    int getCols() const {
        return cols;
    }

    int& operator()(int r, int c) {
        return data[r][c];
    }

    const int& operator()(int r, int c) const {
        return data[r][c];
    }

    Matrix operator+(const Matrix& other) const {
        if (rows != other.rows || cols != other.cols) {
            throw std::invalid_argument("Matrices must have the same dimensions");
        }
        Matrix result(rows, cols);
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < cols; j++) {
                result(i, j) = (*this)(i, j) + other(i, j);
            }
        }
        return result;
    }

    Matrix operator*(const Matrix& other) const {
        if (cols != other.rows) {
            throw std::invalid_argument("Number of columns in first matrix must equal number of rows in second matrix");
        }
        Matrix result(rows, other.cols);
        for (int i = 0; i < rows; i++) {
            for (int j = 0; j < other.cols; j++) {
                int sum = 0;
                for (int k = 0; k < cols; k++) {
                    sum += (*this)(i, k) * other(k, j);
                }
                result(i, j) = sum;
            }
        }
        return result;
    }

    friend std::ostream& operator<<(std::ostream& os, const Matrix& matrix) {
        for (int i = 0; i < matrix.rows; i++) {
            for (int j = 0; j < matrix.cols; j++) {
                os << matrix(i, j) << " ";
            }
            os << std::endl;
        }
        return os;
    }
};

int main() {
    Matrix A(2, 3);
    A(0, 0) = 1;
    A(0, 1) = 2;
    A(0, 2) = 3;
    A(1, 0) = 4;
    A(1, 1) = 5;
    A(1, 2) = 6;

    Matrix B(3, 2);
    B(0, 0) = 7;
    B(0, 1) = 8;
    B(1, 0) = 9;
    B(1, 1) = 10;
    B(2, 0) = 11;
    B(2, 1) = 12;

    Matrix C = A * B;
    std::cout << C << std::endl;
    
    return 0;
}

这个矩阵类支持矩阵的加法和乘法运算，并可以通过重载 `operator()` 实现类似数组下标的访问方式。在 `main` 函数中，我们定义了两个矩阵 `A` 和 `B`，然后计算它们的乘积 `C`，并将结果输出到控制台上。