foo.cc: In function 'int main()':
foo.cc:7:20: error: 'day' was not declared in this scope
  cin>>year>>month>>day;
                    ^~~
foo.cc:7:20: note: suggested alternative: 'days'
  cin>>year>>month>>day;
                    ^~~
                    days
foo.cc: At global scope:
foo.cc:20:2: error: expected unqualified-id before 'else'
  else if(month==4)
  ^~~~
foo.cc:24:5: error: expected unqualified-id before 'else'
     else if(month==5)
     ^~~~
foo.cc:28:5: error: expected unqualified-id before 'else'
     else if(month==6)
     ^~~~
foo.cc:32:2: error: expected unqualified-id before 'else'
  else if(month==7)
  ^~~~
foo.cc:36:2: error: expected unqualified-id before 'else'
  else if(month==8)
  ^~~~
foo.cc:40:2: error: expected unqualified-id before 'else'
  else if(month==9)
  ^~~~
foo.cc:44:5: error: expected unqualified-id before 'else'
     else if(month==10)
     ^~~~
foo.cc:48:6: error: expected unqualified-id before 'else'
      else if(month==11)
      ^~~~
foo.cc:52:10: error: expected unqualified-id before 'else'
          else if(month==12)
          ^~~~
foo.cc:56:2: error: expected unqualified-id before 'return'
  return 0;
  ^~~~~~
foo.cc:57:1: error: expected declaration before '}' token
 }
 ^

[Hydro](https://hydro.ac)提供评测服务