/in/foo.cc: In function 'int main()':
/in/foo.cc:8:9: error: 'days' was not declared in this scope
         days=31;
         ^~~~
/in/foo.cc:10:9: error: 'days' was not declared in this scope
         days=30;
         ^~~~
/in/foo.cc:13:22: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
         if(year%4==0 && year%100!=0 || year%400==0)
            ~~~~~~~~~~^~~~~~~~~~~~~~
/in/foo.cc:14:13: error: 'days' was not declared in this scope
             days=28;
             ^~~~
/in/foo.cc:16:11: error: 'days' was not declared in this scope
     cout<<days;
           ^~~~
/in/foo.cc:5:19: warning: unused variable 'daya' [-Wunused-variable]
    int year,month,daya;
                   ^~~~