怎么用c语言输出一个空心正方形

#include <stdio.h>

int main() { int side; printf(“请输入正方形的边长：”); scanf(“%d”, &side);

for (int i = 1; i <= side; i++) { for (int j = 1; j <= side; j++) { if (i == 1 || i == side || j == 1 || j == side) { printf("*"); } else { printf(" "); } } printf("\n"); } return 0; 

}