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;

}