题解 | 空心正方形图案

#include <stdio.h>

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

    }
    return 0;
}