1*67e74705SXin Li #ifndef C_H 2*67e74705SXin Li #define C_H 3*67e74705SXin Li #include "a.h" 4*67e74705SXin Li #include "b.h" 5*67e74705SXin Li const int c = a+b; 6*67e74705SXin Li #endif 7