foo.cc: In function 'bool f(int)':
foo.cc:7:41: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    7 |  if (year % 400 == 0 || year % 100 != 0 && year % 4 == 0) return true;
      |                         ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:129:12: warning: unused variable 'j' [-Wunused-variable]
  129 |  int x, i, j;
      |            ^
foo.cc:133:19: warning: unused variable 't' [-Wunused-variable]
  133 |  person* p[10], * t = new person;
      |                   ^

[Hydro](https://hydro.ac)提供评测服务