如何将矩阵写入csv C++

#include <iostream>
#include <fstream>
#include <vector>

void writeMatrixToCSV(const std::vector<std::vector<double>>& matrix, const std::string& filename) {
    std::ofstream file(filename);
    if (!file.is_open()) {
        std::cerr << "Error: Could not open the file - " << filename << std::endl;
        return;
    }

    for (const auto& row : matrix) {
        for (size_t i = 0; i < row.size(); ++i) {
            file << row[i];
            if (i != row.size() - 1) {
                file << ",";
            }
        }
        file << "\n";
    }

    file.close();
}

int main() {
    std::vector<std::vector<double>> matrix = {
        {1.1, 2.2, 3.3},
        {4.4, 5.5, 6.6},
        {7.7, 8.8, 9.9}
    };

    writeMatrixToCSV(matrix, "output.csv");

    return 0;
}