题解 | #空心正方形图案#

#include <stdio.h>
int main() {
    //看成矩阵
    int n = 0;
    while (scanf("%d", &n) != EOF) {
        for (int i = 0; i < n; i++) { //行
            for (int j = 0; j < n; j++) { //列
                if (i == 0 || j == 0 || i == n - 1 || j == n - 1) {
                    printf("* ");
                } else {
                    printf("  ");
                }
            }
            printf("\n");
        }
    }
    return 0;
}