c++ difference from java
1. take charge of object management , negotiate ownershiop ,use scoped_ptr,
not to transfer other's ownership
2. use c++ template to express seperation corncern ,such as (static)polymorphy and policy
3. disable copy constructor and assign operator by yourself
4. polymorphy by pointer
5. 使用 template ,macro 取得类似动态语言的能力
6. 偏好无状态的 函数