Warning: assignmentfromincompatiblepointertype

Warning: assignmentfromincompatiblepointertype -- Linux general technology-Linux technology and application information. Read the following for details. # Include
2 # include
3
4 typedef struct student stu_t, * pstu_t;
5
6 struct student
7 {
8 int id;
9 struct stu_t * next;
10 };
11
12 pstu_t create (int id)
13 {
14 pstu_t p = (pstu_t) malloc (sizeof (stu_t ));
15 p-> id = id;
16 p-> next = NULL;
17 return p;
18}
19
20 pstu_t append (pstu_t h, pstu_t t)
21 {
22
23 pstu_t p;
24 if (h = NULL)
25 return t;
26 for (p = h; p-> next! = NULL; p = p-> next)
27;
28 p-> next = t;
29 return h;
30}
31
32 void travel (pstu_t h)
33 {
34 pstu_t p;
35 for (p = h; p-> next! = H; p = p-> next)
36 {
37 printf ("id = % d \ n", p-> id );
38}
39 printf ("id = % d \ n", p-> id );
40}
41
42
43 int main (int argc, const char * argv [])
44 {
45 pstu_t head = NULL;
46 pstu_t t, tail, delp;
47 int I, count = 0;
48 // for (I = 0; I <8; I ++)
49 //{
50 // t = create (I + 1 );
51 // head = append (head, t );
52 //}
53
54 t = create (1 );
55 head = t-> next = t;
56 tail = t;
57 for (I = 1; I <10; I ++)
58 {
59 t = create (I + 1 );
60 t-> next = tail-> next;
61 tail = tail-> next = t;
62}
63 travel (head );
64 t = tail;
65 printf ("the key is :");
66 while (t-> next! = T)
67 {
68 t = t-> next;
69 count ++;
70 if (count> = 2)
71 {
72 count = 0;
73 delp = t-> next;
74 t-> next = delp-> next;
75 printf ("% d", delp-> id );
76}
77}
78 printf ("\ n ");
79 printf ("the last kill is: % d \ n", t-> id );
80 // return 0;
81}

Assignment from incompatible pointer type: What is this warning ??