怎么不使用数组编译一个这样的螺旋方阵？

#include <iostream>
#include <vector>

using std::cout;
using std::cin;
using std::endl;
using std::vector;

int main(void)
{

    int n = 0;
    cin >> n;
    vector<vector<int>> ivec(n ,vector<int>(n, 0));
    int dir = 1;
    int x = 0;
    int y = 0;
    int i = 1;
    for (i = 1; i <= n*n;)
    {
        switch (dir)
        {
        case 1:
            for (;y != n; ++y)
            {
                if (ivec[x][y] != 0)
                    break;
                ivec[x][y] = i++;
                // cout << "(" << x << ", " << y << ") = " << i-1 << endl;
            }
            --y;
            ++x;
            ++dir;
            break;
        case 2:
            for (;x != n; ++x)
            {
                if (ivec[x][y] != 0)
                    break;
                ivec[x][y] = i++;
                // cout << "(" << x << ", " << y << ") = " << i-1 << endl;
            }
            --x;
            --y;
            ++dir;
            break;
        case 3:
            for (;y >= 0; --y)
            {
                if (ivec[x][y] != 0)
                    break;
                ivec[x][y] = i++;
                // cout << "(" << x << ", " << y << ") = " << i-1 << endl;
            }
            ++y;
            --x;
            ++dir;
            break;
        case 4:
            for (;x >= 0; --x)
            {
                if (ivec[x][y] != 0)
                    break;
                ivec[x][y] = i++;
                // cout << "(" << x << ", " << y << ") = " << i-1 << endl;
            }
            ++x;
            ++y;
            dir = 1;
            break;
        default:
            break;
        }
    }
    for (x = 0; x != n; ++x)
    {
        for (y = 0; y != n; ++y)
            cout << ivec[x][y] << "\t";
        cout << endl;
    }
    return 0;
}