foo.cc:22:33: error: stray ‘@’ in program
   22 |  12209水宇辰 (12209水宇辰) LV 9 @ 3 年前
      |                                 ^
foo.cc:20:1: error: expected unqualified-id before numeric constant
   20 | 1
      | ^
foo.cc:25:5: error: redefinition of ‘int main()’
   25 | int main()
      |     ^~~~
foo.cc:3:5: note: ‘int main()’ previously defined here
    3 | int main()
      |     ^~~~