数据结构——双向链表相关操作

#include
#include
#include
#define OK 1
#define ERROR 0
#define TRUE 1
#define FALSE 0

typedef int status;
typedef int elemtype;

typedef struct node {
	elemtype data;
	struct node * next;
	struct node * prior;
} node;

typedef struct node* dlinklist;

status visit(elemtype c) {
	printf("%d ",c);
}

/*双向链表初始化*/
status initdlinklist(dlinklist * head,dlinklist * tail) {
	(*head)=(dlinklist)malloc(sizeof(node));
	(*tail)=(dlinklist)malloc(sizeof(node));
	if(!(*head)||!(*tail))
		return ERROR;
	/*这一步很关键*/
	(*head)->prior=NULL;
	(*tail)->next=NULL;
	/*链表为空时让头指向尾*/
	(*head)->next=(*tail);
	(*tail)->prior=(*head);
}

/*判定是否为空*/
status emptylinklist(dlinklist head,dlinklist tail) {
	if(head->next==tail)
		return TRUE;
	else
		return FALSE;
}

/*尾插法创建链表*/
status createdlinklisttail(dlinklist head,dlinklist tail,elemtype data) {
	dlinklist pmove=tail,pinsert;
	pinsert=(dlinklist)malloc(sizeof(node));
	if(!pinsert)
		return ERROR;
	pinsert->data=data;
	pinsert->next=NULL;
	pinsert->prior=NULL;
	tail->prior->next=pinsert;
	pinsert->prior=tail->prior;
	pinsert->next=tail;
	tail->prior=pinsert;
}

/*头插法创建链表*/
status createdlinklisthead(dlinklist head,dlinklist tail,elemtype data) {
	dlinklist pmove=head,qmove=tail,pinsert;
	pinsert=(dlinklist)malloc(sizeof(node));
	if(!pinsert)
		return ERROR;
	else {
		pinsert->data=data;
		pinsert->prior=pmove;
		pinsert->next=pmove->next;
		pmove->next->prior=pinsert;
		pmove->next=pinsert;
	}
}

/*正序打印链表*/
status traverselist(dlinklist head,dlinklist tail) {
	/*dlinklist pmove=head->next;
	while(pmove!=tail){
	  printf("%d ",pmove->data);
	  pmove=pmove->next;
	}
	printf("\n");
	return OK;*/
	dlinklist pmove=head->next;
	while(pmove!=tail) {
		visit(pmove->data);
		pmove=pmove->next;
	}
	printf("\n");
}

/*返回第一个值为data的元素的位序*/
status locateelem(dlinklist head,dlinklist tail,elemtype data) {
	dlinklist pmove=head->next;
	int pos=1;
	while(pmove&&pmove->data!=data) {
		pmove=pmove->next;
		pos++;
	}
	return pos;
}

/*返回表长*/
status listlength(dlinklist head,dlinklist tail) {
	dlinklist pmove=head->next;
	int length=0;
	while(pmove!=tail) {
		pmove=pmove->next;
		length++;
	}
	return length;
}

/*逆序打印链表*/
status inverse(dlinklist head,dlinklist tail) {
	dlinklist pmove=tail->prior;
	while(pmove!=head) {
		visit(pmove->data);
		pmove=pmove->prior;
	}
	printf("\n");
}

/*删除链表中第pos个位置的元素，并用data返回*/
status deleteelem(dlinklist head,dlinklist tail,int pos,elemtype *data) {
	int i=1;
	dlinklist pmove=head->next;
	while(pmove&&i) {
		pmove=pmove->next;
		i++;
	}
	if(!pmove||i>pos) {
		printf("输入数据非法\n");
		return ERROR;
	} else {
		*data=pmove->data;
		pmove->next->prior=pmove->prior;
		pmove->prior->next=pmove->next;
		free(pmove);
	}
}

/*在链表尾插入元素*/
status inserttail(dlinklist head,dlinklist tail,elemtype data) {
	dlinklist pinsert;
	pinsert=(dlinklist)malloc(sizeof(node));
	pinsert->data=data;
	pinsert->next=NULL;
	pinsert->prior=NULL;
	tail->prior->next=pinsert;
	pinsert->prior=tail->prior;
	pinsert->next=tail;
	tail->prior=pinsert;
	return OK;
}
int main(void) {
	dlinklist head,tail;
	int i=0;
	elemtype data=0;
	initdlinklist(&head,&tail);
	if(emptylinklist(head,tail))
		printf("链表为空\n");
	else
		printf("链表不为空\n");
	printf("头插法创建链表\n");
	for(i=0; i<10; i++) {
		createdlinklisthead(head,tail,i);
	}
	traverselist(head,tail);

	for(i=0; i<10; i++) {
		printf("表中值为%d的元素的位置为",i);
		printf("%d位\n",locateelem(head,tail,i));
	}
	printf("表长为%d\n",listlength(head,tail));
	printf("逆序打印链表");
	inverse(head,tail);
	for(i=0; i<10; i++) {
		deleteelem(head,tail,1,&data);
		printf("被删除的元素为%d\n",data);
	}
	traverselist(head,tail);
	if(emptylinklist(head,tail))
		printf("链表为空\n");
	else
		printf("链表不为空\n");
	printf("尾插法创建链表\n");
	for(i=0; i<10; i++) {
		//inserttail(head,tail,i);
		createdlinklisttail(head,tail,i);
	}
	traverselist(head,tail);
	printf("逆序打印链表");
	inverse(head,tail);
}