Data structure-bidirectional circular linked list (headless node) correlation algorithm

#include <stdio.h>
#include <stdlib.h>
#define OVERFLOW-2
#define OK 1
#define ERROR 0

//This bidirectional loop linked list headless node
typedef int ELEMTYPE;
typedef struct DULNODE {
Elemtype data;
struct Dulnode *prior;
struct Dulnode *next;
}dulnode,*dullinklist;

dullinklist Initlist_dul (dullinklist L);
dullinklist Createelemp_dul (dullinklist L);
void Printlist_dul (Dullinklist L);
int Getelemp1_dul (dullinklist l,int i,elemtype *e);
dullinklist Listinsert_dul (dullinklist l,int i,elemtype e);
int Listlength_dul (dullinklist L);
dullinklist Getelemp2_dul (dullinklist l,int i);
dullinklist Listinsert_dul (dullinklist l,int i,elemtype e);
dullinklist Listdelete_dul (dullinklist l,int i,elemtype *e);
int Getlocate_dul (dullinklist l,elemtype e);
int main ()
{
Dullinklist Dul;
int len,loc;
Elemtype e;
Dul = Initlist_dul (Dul);
Dul = Createelemp_dul (Dul);
Len = Listlength_dul (Dul);
printf ("The length of the doubly linked list is:%d\n", Len);
Printlist_dul (Dul);
Getelemp1_dul (dul,3,&e);//3 is the bit sequence where the element resides
printf ("The element of the first position is:%d\n", e);
printf ("After inserting an element into the list:");
Dul = Listinsert_dul (dul,1,0);//1 The position of the insertion element
Printlist_dul (Dul);
printf ("After deleting an element from a linked list:");
Dul = Listdelete_dul (dul,2,&e);//2 the bit order to delete the element
Printlist_dul (Dul);
printf ("The deleted element is:%d\n", e);
loc = Getlocate_dul (dul,0);//0 is the value of the element
printf ("The sequence of the two-way cyclic linked list element i is:%d\n", loc);
return 0;
}

//Initialize a two-way loop linked list
Dullinklist Initlist_dul (dullinklist L) {
L = (dullinklist) malloc (sizeof (Dulnode));
if (L! = NULL) {
L->next = L->prior = L;
} else {
Exit (OVERFLOW);
}
return L;

}

//Create a two-way circular linked list
Dullinklist Createelemp_dul (dullinklist L) {
int n,i;
Dullinklist P,s;
s = L;
printf ("Please enter the number of elements of the bidirectional loop list:");
scanf ("%d", &n);
printf ("Please enter the value of the element in the doubly-looped list:");
for (i=0; i<n; i++) {
p = (dullinklist) malloc (sizeof (Dulnode));
scanf ("%d", &p->data);
P->prior = s->prior;
S->prior->next = p;
P->next = s;
S->prior = p;
}
return L;
}

//Output the bidirectional loop linked list
void Printlist_dul (Dullinklist L) {
int i;
Dullinklist p;
p = L;
printf ("The element in the loop-linked list is:");
while (p->next! = L) {
p = p->next;
printf ("%d", p->data);
}
printf ("\ n");
}

//Returns the length of the double-loop linked list
int Listlength_dul (dullinklist L) {
Dullinklist p;
int i;
p = l->next;
i = 0;
while ((p!=l) && (p!=null)) {
++i;
p = p->next;
}
return i;
}

//Get the value of the element on the I-position in the two-way loop linked list
int Getelemp1_dul (dullinklist l,int i,elemtype *e) {
Dullinklist p;
Int J;
p = L;
j = 0;
while (P->next && j<i) {
++j;
p = p->next;
}
if (!p | | j>i) return ERROR;
*e = p->data;
return OK;
}

//Returns the pointer on the I position on the double-loop linked list
Dullinklist Getelemp2_dul (dullinklist l,int i) {
Dullinklist p;
Int J;
p = L;
j = 0;
while (P->next && j<i) {
++j;
p = p->next;
}
if (!p | | j>i) return ERROR;
return p;
}

//To insert element e before the I position of the two-way loop linked list
Dullinklist Listinsert_dul (dullinklist l,int i,elemtype e) {
Dullinklist P,s;
int m;
if (! ( P=getelemp2_dul (l,i))) {
return ERROR;
}

if (! ( s = (dullinklist) malloc (sizeof (Dulnode)))) {
return ERROR;
}
S->data = e;
S->prior = p->prior;
P->prior->next = s;
S->next = p;
P->prior = s;
return L;
}

//Delete the element on the I-position of the two-way loop linked list and return the value of the element
Dullinklist Listdelete_dul (dullinklist l,int i,elemtype *e) {
Dullinklist p;
if (! ( P=getelemp2_dul (l,i))) {
return ERROR;
}
*e = p->data;
P->prior->next = p->next;
P->next->prior = p->prior;
return L;
}

//Returns the ordinal of element e on a doubly-linked circular list
int Getlocate_dul (dullinklist l,elemtype e) {
Dullinklist p;
Int J;
p = l->next;
j = 0;
while ((P! = L) && (p->data!=e)) {
j + +;
}
Return J;
}

Data structure-bidirectional circular linked list (headless node) correlation algorithm