螺旋输出N*N矩阵

#include <iostream>
#include <vector>
using namespace std;
int main() {
    int x[] = { 0, 1, 0, -1 };
    int y[] = { 1, 0, -1, 0 };
    int n;
    int pos_x = 0;
    int pos_y = 0;
    cin >> n;
    int counter = 1;
    vector<vector<int> > A(n, vector<int>(n, 0));
    int i;
    for (i = n - 1; i > 0; i -= 2) {
        for (int k = 0; k < 4; k++) {
            for (int j = 0; j < i; j++) {
                A[pos_x][pos_y] = counter;
                counter++;
                pos_x += x[k];
                pos_y += y[k];
            }
        }
        pos_x++;
        pos_y++;
    }
    if (i == 0)
        A[pos_x][pos_y] = counter;
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            cout << A[i][j] << "  ";
        }
        cout << endl;
    }
    return 0;
}