谁帮我看看这道笔试题的printf语句，居然看不懂...

main()
{
int i;
for(i=0;i<=N;i++)
{
    printf("%*.*s%-*.*s\n",N,i<=N/2?i:N-i,"*******************",N,i<=N/2?i+1:N
-i+1,"*******************");
}

}