/in/foo.cc: In function 'int main()':
/in/foo.cc:25:16: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    if(year%4==0&&year%100!=0||year%400==0)
       ~~~~~~~~~^~~~~~~~~~~~~
/in/foo.cc:30:9: warning: 'days' may be used uninitialized in this function [-Wmaybe-uninitialized]
   cout<<days<<endl;
         ^~~~