1> 数据类型  基本类型     char int float double

                                    signed unsigned short long

                   派生类型     struct union enum

                   指针/空类型 void

                   类型定义     typedef

2> 尺寸算符                   sizeof

3> 常量修饰                   const volatile

4> 存储类别                   static extern auto register

5> 控制结构  分支控制     if else switch case default

                   循环控制     do while for

                   转向控制     break continue return goto