题解 | #空心正方形图案#

#include <stdio.h>

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