/in/foo.cc: In function 'int rn(int)':
/in/foo.cc:12:11: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   12 |  if(a%4==0&&a%100!=0||a%400==0) return 1;
      |     ~~~~~~^~~~~~~~~~
/in/foo.cc: In function 'bool cmp(date, date)':
/in/foo.cc:23:1: warning: control reaches end of non-void function [-Wreturn-type]
   23 | }
      | ^