선형 표 의 이중 순환 링크

#include<stdio.h>
#include<stdlib.h>

#define OK 1
#define ERROR 0

typedef int Elemtype;
typedef int Status;

typedef struct Node{
	Elemtype data;
	struct Node* prior;
	struct Node* next;
}Node;
typedef struct Node* DolLinkList;

Status InitDolLinkList(DolLinkList *DL){
	*DL = (DolLinkList)malloc(sizeof(struct Node));
	if(!(*DL))
		return ERROR;
	(*DL)->next = *DL;
	(*DL)->prior = *DL;
	return OK;
}
Status ClearDolLinkList(DolLinkList DL){
//           
	DolLinkList s,f = DL->next;
	while(f != DL){
		s = f;
		f = f->next;
		free(s);
	}
	DL->next = DL;
	DL->prior = DL;
	return OK;
}
Status DestoryDolLinkList(DolLinkList DL){
	ClearDolLinkList(DL);
	free(DL);
	DL = NULL;
}
int Length_DolLinkList(DolLinkList DL){
	int length = 0;
	DolLinkList t = DL->next;
	while(t != DL){
		t = t->next;
		length++;
	}
	return length;
}
Status GetElement_DolLinkList(DolLinkList DL,int position,int *value){
	int count = 0;
	int length = Length_DolLinkList(DL);
	if(position < 1 || position > length){
		return ERROR;
	}
	else{
		while(count < position){
			DL = DL->next;
			count++;
		}
		*value = DL->data;
		return OK;
	}
}
Status LocateElement_DolLinkList(DolLinkList DL,Elemtype value,int *position){
	*position = 1;
	DolLinkList t = DL->next;
	while(t != DL){
		if(t->data == value){
			return OK;	
		}
		t = t->next;
		(*position)++;
	}
	return ERROR;
}
Status GetPriorElement_DolLinkList(DolLinkList DL,int currentElement,int *priorElement){
	int r1;
	int count = 0;
	if(LocateElement_DolLinkList(DL,currentElement,&r1)){
		while(count < r1){
			count++;
			DL = DL->next;
		}
		if(count == 1)
			*priorElement = DL->prior->prior->data;
		else
			*priorElement = DL->prior->data;
		return OK;
	}
	else
		return ERROR;
}
Status GetNextElement_DolLinkList(DolLinkList DL,int currentElement,int *nextElement){
	int r1;
	if(LocateElement_DolLinkList(DL,currentElement,&r1)){
		int count = 0;
		while(count < r1){
			count++;
			DL = DL->next;
		}
		if(count == Length_DolLinkList(DL))
			*nextElement = DL->next->next->data;
		else
			*nextElement = DL->next->data;
		return OK;
	}
	else
		return ERROR;
}
Status Insert_DolLinkList(DolLinkList DL,int position,int value){
	if(position < 1 || position > Length_DolLinkList(DL) + 1)
		return ERROR;
	else{
		int count = 0;
		while(count < position){
			count++;
			DL = DL->next;
		}
		DolLinkList new = (DolLinkList)malloc(sizeof(struct Node));
		new->data = value;
		new->prior = DL->prior;
		DL->prior->next = new;
		new->next = DL;
		DL->prior = new;
		return OK;
	}
}
Status Delete_DolLinkList(DolLinkList DL,int position,int *value){
	if(position < 1 || position > Length_DolLinkList(DL))
		return ERROR;
	else{
		int count = 0;
		while(count < position){
			count++;
			DL = DL->next;
		}
		*value = DL->data;
		DL->next->prior = DL->prior;
		DL->prior->next = DL->next;
		free(DL);
	}
}
Status CreateDolLinkList_TailInsert(DolLinkList DL,int number){
	DolLinkList new;
	int i;
	printf("PLEASE ENTER %d ELEMNET!
",number);
	for(i = 1; i <= number; i++){
		new = (DolLinkList)malloc(sizeof(struct Node));
		if(!new)
			return ERROR;
		printf("please enter element%d:   ",i);
		scanf("%d",&(new->data));
		new->prior = DL->prior;
		new->next = DL;
		DL->prior->next = new;
		DL->prior = new;
	}
	return OK;
}
void DisplayDolLinkList(DolLinkList DL){
	DolLinkList temp = DL;
	while(temp->next != DL){
		temp = temp->next;
		printf("%d ",temp->data);
	}
	printf("
Display Executed!

");
}
int main(){
	DolLinkList DL;
	InitDolLinkList(&DL);
	CreateDolLinkList_TailInsert(DL,5);
	printf("the length of list is %d
",Length_DolLinkList(DL));
	DisplayDolLinkList(DL);
	
	int r1,r2;
	if(GetElement_DolLinkList(DL,3,&r1))
		printf("the element of postion 3 is %d
",r1);
	else
		printf("Error:getElement:position
");
	if(GetElement_DolLinkList(DL,6,&r2))
		printf("the element of postion 6 is %d
",r2);
	else
		printf("Error:getElement:position
");

	if(LocateElement_DolLinkList(DL,4,&r1))
		printf("the position of element 4 is %d
",r1);
	else
		printf("Error:LocateElement:value
");
	if(LocateElement_DolLinkList(DL,8,&r1))
		printf("the position of element 8 is %d
",r1);
	else
		printf("Error:LocateElement:value
");

	if(GetPriorElement_DolLinkList(DL,6,&r1))
		printf("before the 6 is %d
",r1);
	else
		printf("Error:GetPriorElement:currentElement
");
	if(GetPriorElement_DolLinkList(DL,1,&r2))
		printf("before the 1 is %d
",r2);
	else
		printf("Error:GetPriorElement:currentElement
");
	
	if(GetNextElement_DolLinkList(DL,2,&r1))
		printf("next the 2 is %d
",r1);
	else
		printf("Error:nextElement:currentElement
");
	if(GetNextElement_DolLinkList(DL,5,&r1))
		printf("next the 5 is %d
",r1);
	else
		printf("Error:nextElement:currentElement
");
	
	Insert_DolLinkList(DL,3,666);
	Insert_DolLinkList(DL,7,999);
	Insert_DolLinkList(DL,1,111);
	Insert_DolLinkList(DL,9,2222);
	DisplayDolLinkList(DL);

	Delete_DolLinkList(DL,2,&r1);
	Delete_DolLinkList(DL,8,&r1);
	DisplayDolLinkList(DL);
	return 0;
}