题解 | #空心正方形图案#

int main()

{

    int i,j,n;

    while(scanf("%d",&n) != EOF)

    {

        for(i = 1;i<=n;i++)

        {

            for(j = 1;j<=n;j++)

            {

                if(i == 1||i==n)

                {

                    printf("* ");

                }

                else if((j == 1&&i!=1)||(j==n&&i!=n))

                {

                    printf("* ");

                }

                else

                {

                    printf("  ");

                }

            }

            printf("\n");       

        }

    }

    return 0;

}