When starting to learn the binary tree, I find that I am not clear with the struct.So here comes this note.

First, when it comes to Struct, it may like this.

struct Table{

      int legs;

      char name;

};

However, mostly we use it like this.

typedef struct Table{

int legs;

struct Table *next;

char name;

}Table,*TableList;

so, what does typedef, Table,*TableList mean?

if you use typedef in the code above, it means the Table[structure tag] could be used to create Struct type variable like      Table t;  t.legs=4;   the Table behalf of the structure.                                                                                          

if there is no typedef, you have to write      struct Table t      each time you create a structure type variable. 

The difference is to write struct or not, that typedef brings.

if we omit the structure tag,

typedef struct {

int legs;

struct Table *next;

char name;

}Table,*TableList;

the Table is the only one structure entity we could use.

The *TableList is a structure pointer, a pointer point to the struct node. 

Things get different in C++

typedef struct Table{

int legs;

}Table1;

The Table1 is a structure entity , use 

Table1 t; 

t.legs=4; 

struct Table{

int legs;

}Table2;

TheTable2 is a structure variable, use 

Table2.legs=4;

updating ........