题解 | #空心正方形图案#

#include <stdio.h>
int main() {
    int n = 0;
    while (scanf("%d", &n) != EOF) {
        for (int i = 0; i < n; i++) { //外循环为行
            for (int j = 0; j < n; j++) { //内循环为列
                if (i == 0 || i == n - 1 || j == 0 || j == n - 1)//找规律
                    printf("* ");
                else
                    printf("  ");
            }
            printf("\n");
        }
    }
}