题解 | #空心正方形图案#

#include <stdio.h>

int main() {
    int n = 0;
    while (~scanf("%d", &n)) {
        int i;
        for (i = 0; i < n; i++) {
            int j;
            for (j = 0; j < n; j++) {
                if (i == 0 || i == n - 1)
                    printf("* ");
                else if (j == 0 || j == n - 1)
                    printf("* ");
                else
                    printf("  ");
            }
            printf("\n");
        }
    }
    return 0;
}