how to delete text lines ?

how to delete text lines ?

Please tell me how to design a script

#ifdef __cplusplus
#include  aaaa.h
....
#else
#include bbbbbbbb.h
....
#include cccccc.h
#endif

become the form of

#include bbbbbbbb.h
.....
#inlude  cccccc.h      
删除#开头的行吗?      
不是,
在if -else-fi中,只留else和fi之间的内容。

thinks      

grep -v ^#ifdef yourfile|grep -v ^#else