/in/foo.cc: In function 'int main()':
/in/foo.cc:21:3: error: 'days' was not declared in this scope
   days=1;
   ^~~~
/in/foo.cc:23:7: warning: unused variable 'days' [-Wunused-variable]
   int days=0;
       ^~~~
/in/foo.cc:28:3: error: 'days' was not declared in this scope
   days++;
   ^~~~
/in/foo.cc:30:8: error: 'days' was not declared in this scope
  cout<<days-1<<endl;
        ^~~~