Spiral

#include <iostream>

using namespace std;

void left(int& i, int& j)
{
    j--;
}

void right(int& i, int& j)
{
    j++;
}

void up(int& i, int& j)
{
    i--;
}

void down(int& i, int& j)
{
    i++;
}

int b[5][5] = {{0, 0, 0, 0, 0},
               {0, 0, 0, 0, 0},
               {0, 0, 0, 0, 0},
               {0, 0, 0, 0, 0},
               {0, 0, 0, 0, 0}};

bool isFree(int i, int j, int n)
{
    if (b[i][j] != 0 || i < 0 || i >= n || j < 0 || j >= n)
    {
        return false;
    }
    return true;
}

int main()
{
    int n = 5;
    int a[5][5] = {{1, 2, 3, 4, 5},
                  {6, 7, 8, 9, 10},
                  {11, 12, 13, 14, 15},
                  {16, 17, 18, 19, 20},
                  {21, 22, 23, 24, 25}};

                  /*
    int si = 0, sj = 0;

    for (int k = 0; k <= n / 2; k++)
    {
        while (isFree(si, sj, n))
        {
            b[si][sj] = 1;
            cout << a[si][sj] << " ";
            right(si, sj);
        }
        sj--;
        si++;
        while (isFree(si, sj, n))
        {
            b[si][sj] = 1;
            cout << a[si][sj] << " ";
            down(si, sj);
        }
        sj--;
        si--;
        while (isFree(si, sj, n))
        {
            b[si][sj] = 1;
            cout << a[si][sj] << " ";
            left(si, sj);
        }
        si--;
        sj++;
        while (isFree(si, sj, n))
        {
            b[si][sj] = 1;
            cout << a[si][sj] << " ";
            up(si, sj);
        }
        si++;
        sj++;
    }
    */

    // dlur
    int si = 0, sj = n - 1;

    for (int k = 0; k <= n / 2; k++)
    {
        while (isFree(si, sj, n))
        {
            b[si][sj] = 1;
            cout << a[si][sj] << " ";
            down(si, sj);
        }
        sj--;
        si--;
         while (isFree(si, sj, n))
        {
            b[si][sj] = 1;
            cout << a[si][sj] << " ";
            left(si, sj);
        }
        si--;
        sj++;
        while (isFree(si, sj, n))
        {
            b[si][sj] = 1;
            cout << a[si][sj] << " ";
            up(si, sj);
        }
        si++;
        sj++;
        while (isFree(si, sj, n))
        {
            b[si][sj] = 1;
            cout << a[si][sj] << " ";
            right(si, sj);
        }
        sj--;
        si++;
    }
    return 0;
}