回文方阵

#include <iostream>

using namespace std;

int k = 1;

const int N = 100;
int a[N][N];
int n;

void matrix(int p,int q)
{

  if(k==n*n+1) return;

  for(int i = q;i<=p;i++) a[i][p] = k++;
  for(int i = p-1;i>=q;i--) a[p][i] = k++;
  for(int i = p-1;i>=q;i--) a[i][q] = k++;
  for(int i = q+1;i<p;i++) a[q][i] = k++;

  q++,p--;

  matrix(p,q);
}

int main()
{
  while(scanf("%d",&n)!=EOF)
  {
    k = 1;
    matrix(n,1);

    for(int i = 1;i<=n;i++)
    {
      for(int j = 1;j<=n;j++)
      {
        cout << a[i][j] << " ";
      }
      puts("");
    }
  }
  return 0;

}