C++ 幻方程序设计

#include<iostream>
using namespace std;
int main()
{
int n;
int i,j,k;
cout<<"请输入幻方阶数:";
cin>>n;
int **a=new int*[n];
for(i=0;i<n;i++)
   a[i]=new int[n];
if(n%2==1)//奇数阶
{
   for(i=0;i<n;i++)
    for(j=0;j<n;j++)
     a[i][j]=0;
   i=0;
   j=n/2;
   k=1;
   a[i][j]=k;
   for(k=2;k<=n*n;k++)
   {
    i--;
    j++;
    if(i==n-1&&j==n-1)
    {
     i++;
     a[i][j]=k;
     break;
    }

    if(i<0)
     i=n-1;
    if(j>n-1)
     j=0;
    if(a[i][j]==0)
     a[i][j]=k;
    else
    {
     i++;
     if(i>n-1)
      i=0;
     j--;
     if(j<0)
      j=n-1;
     i++;
     if(i>n-1)
      i=0;
     a[i][j]=k;
    }
   }
}
else if(n%4==0)//双偶数阶
{
   int nn=(n+1)/4;//一共有nn*nn个4方格
   int ii,jj;
   k=1;
   for(i=0;i<n;i++)
    for(j=0;j<n;j++)
     a[i][j]=k++;
   k=n*n+1;