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; 

}