/in/foo.cc:9:17: warning: missing terminating " character
  printf("2.1"%d ",x);
                 ^
/in/foo.cc:9:17: error: missing terminating " character
  printf("2.1"%d ",x);
                 ^~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:9:15: error: 'd' was not declared in this scope
  printf("2.1"%d ",x);
               ^