NxN行列式函数(C++)的代码问题

#include <iostream>
#include <vector>

using namespace std;

// 计算NxN行列式的函数
double calculateDeterminant(vector<vector<double>>& matrix) {
    int n = matrix.size();
    double determinant = 0;

    // 递归终止条件：当矩阵为2x2时，直接计算行列式的值
    if (n == 2) {
        return matrix[0][0] * matrix[1][1] - matrix[0][1] * matrix[1][0];
    }

    // 递归计算行列式的值
    for (int i = 0; i < n; i++) {
        vector<vector<double>> subMatrix(n - 1, vector<double>(n - 1, 0));

        for (int j = 1; j < n; j++) {
            for (int k = 0; k < n; k++) {
                if (k < i) {
                    subMatrix[j - 1][k] = matrix[j][k];
                } else if (k > i) {
                    subMatrix[j - 1][k - 1] = matrix[j][k];
                }
            }
        }

        determinant += matrix[0][i] * pow(-1, i) * calculateDeterminant(subMatrix);
    }

    return determinant;
}

int main() {
    // 示例用法
    vector<vector<double>> matrix = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
    double determinant = calculateDeterminant(matrix);

    cout << "Determinant: " << determinant << endl;

    return 0;
}