题解 | 空心正方形图案

#include <stdio.h>

int main(int argc, char const* argv[]) {
    int n = 0;
    int i = 0, j = 0;
    while (scanf("%d", &n) == 1) {
        for (i = 0; i < n; i++) {
            for (j = 0; j < n; j++)
                if (i == 0 || i == n - 1 || j == 0 || j == n - 1)
                    printf("* ");
                else printf("  ");
            putchar('\n');
        }
    }
    return 0;
}