#define n 4
    
int A[n][n]={{1,2,3,4},{5,6,7,8},{9,10,11,12},
{13,14,15,16}};
int min=0,max=n-1,i,j;

while(min<max)
{
   for(i=min;i<=max;i++)
       printf("%d,",A[min][i]);
   for(i=min+1;i<=max;i++)
       printf("%d,",A[i][max]);
   for(i=max-1;i>=min;i--)
       printf("%d,",A[max][i]);
   for(i=max-1;i>min;i--)
       printf("%d,",A[i][min]);
   min++;
   max--;
 }