# include 
     
      typedef struct Student  //给数据类型重新定义个名字为 ST{    int sid ;    char name;}ST;typedef struct Student  //给数据类型重新定义个名字为 ST{    int sid ;    char name;}* ST;        //等价于 struct Student * sttypedef struct Student  //给数据类型重新定义个名字为 ST{    int sid ;    char name;}* ST ,SU;        //ST 等价于 struct Student * st, SU 等价于struct Student stint main(void){    ST st; //等价于 struct Student st}