单链表和双链表上的基本操作

//by gigglesun 2010-5-3
#include <stdlib.h>
#include <stdio.h>
#define FALSE 0
#define TRUE 1

/////////////////////////单链表///////////////////////////////////

typedef struct NODE
{
struct NODE *link;
int value;
}Node;

/*creat link list with n node*/
Node* sll_create(unsigned n)
{
Node* head,*s,*p;
int i = 1;
head = p = NULL;

//creat the head node：the first node
if((p = (Node*)malloc(sizeof(Node)))==NULL)
{
printf("An error occurred when malloc new node/n");
exit(0);
}
p->value = 3 * i;
p ->link = NULL;
i += 1;
head = p;
n -= 1;

//creat the second to the n node: link them with the first node
while(n--)
{
if((s = (Node*)malloc(sizeof(Node)))==NULL)
{
printf("An error occurred when malloc new node/n");
exit(0);
}
s->value = 3 * i;
s ->link = NULL;
i += 1;
p->link = s;
p = s;
}
return head;
}

/*use only one pointer to insert node in sorted link list*/
int sll_insert(Node**linkp,int new_value)
{
Node *current;
Node *s;

while((current = *linkp) != NULL && current->value < new_value)
linkp = ¤t->link;
s = (Node*)malloc(sizeof(Node));
if(s == NULL)
return FALSE;
s->value = new_value;
s->link = current;
*linkp = s;
return TRUE;
}

/*delete the node by value*/
void sll_delete(Node **head,int value)
{
Node *p = *head,*pre = *head;
while( p != NULL && p->value != value)
{
pre = p;
p = p->link;
}

if(p == NULL)
{
printf("No node with value %d/n",value);
return ;
}
else
{
if (p == *head)
{
*head = (*head)->link;
free(p);
}
else
{
pre->link = p->link;
free(p);
}
printf("success delete node with value %d/n",value);
}
}

/*print the link list*/
void sll_print(Node* head)
{
Node *p=head;
while(p != NULL)
{
printf("%-4d",p->value);
p = p->link;
}
printf("/n");
}

//////////////////////////双链表/////////////////////////////////////

typedef struct DNODE
{
struct DNODE *fwd;//forward pointer
struct DNODE *bwd;//backward pointer
int value;//length of the link list
} DNode;

//*creat double link list with n node*/
DNode* Dll_create(unsigned int n)
{
DNode *head,*root,*s,*p;//head node： the first node
unsigned int i = 1;
head = p = NULL;

//creat the root node：it contains two pointers:one points to the headnode,the other to the backnode,and the length information.
if((root = (DNode*)malloc(sizeof(DNode)))==NULL)
{
printf("An error occurred when malloc new node/n");
exit(0);
}
root->value = n;//the length of the list
root ->fwd = NULL;
root->bwd = NULL;

//creat the second to the n node: link them with the first node
while(i <= n)
{
if((s = (DNode*)malloc(sizeof(DNode)))==NULL)
{
printf("An error occurred when malloc new node/n");
exit(0);
}
if (i == 1)
{
head = s;
head->value = 3 * i;
head->fwd = NULL;
head->bwd = NULL;
p = head;
}
else
{
s->value = 3 * i;
s->fwd = NULL;
s->bwd = p;
p->fwd = s;
p = s;
}
i += 1;
}
root->fwd = head;
root->bwd = p;
return root;
}

/*Insert node in the double link list*/
int Dll_insert(DNode *root,int value)
{
DNode *pre = root,*q = root->fwd,*newNode = NULL;
while(q != NULL && q->value < value)
{
pre = q;
q = q->fwd;
}
newNode = (DNode*)malloc(sizeof(DNode));
if(newNode == NULL)
return FALSE;
newNode->value = value;
newNode->fwd = newNode->bwd = NULL;
if(q != NULL)
{
pre->fwd = newNode;
if (pre == root)
newNode->bwd = NULL;
else
newNode->bwd = pre;
newNode->fwd = q;
q->bwd = newNode;
}
else
{
pre->fwd = newNode;
newNode->bwd = pre;
root->bwd = newNode;
}
root->value += 1;//length increase
return TRUE;
}

/*Delete node in the double link list*/
int Dll_delete(DNode *root,int value)
{
DNode *pre = root,*q = root->fwd,*newNode = NULL;
while(q != NULL && q->value != value)
{
pre = q;
q = q->fwd;
}
if(q != NULL)
{
if(q->fwd == NULL)
{
pre->fwd =NULL;
free(q);
}
else
{
pre->fwd = q ->fwd;
(q->fwd)->bwd = pre;
free(q);
}
printf("Success delete node with value %d/n",value);
root->value -= 1;//length decrease 1
return TRUE;
}
else
{
printf("No node with value %d/n",value);
return FALSE;
}
}

/*Search node in the  double link list,backwards and forwards simultaneously*/
int Dll_search(DNode *root,int value)
{
int cnt = 1;
DNode *b = root->bwd,*f = root->fwd,*preb = root,*pref = root;
while(f != NULL && b != NULL&& f->value != value && b->value != value)
{
pref = f;
f = f->fwd;
preb = b;
b = b->bwd;
cnt ++;
}
printf("Search %d times/n",cnt);
if(f == NULL || b == NULL)
return FALSE;
else
return TRUE;
}

/*print the double link list*/
void Dll_print(DNode *root)
{
DNode *p = root;
printf("There are %d nodes in this double link list/n",root->value);
//From head to tail print the node
printf("From head to tail,the nodes are:");
p = root->fwd;
while(p != NULL)
{
printf("%4d",p->value);
p = p->fwd;
}
//From tail to head print the node
printf("/nFrom tail to head,the nodes are:");
p = root->bwd;
while( p != NULL)
{
printf("%4d",p->value);
p = p->bwd;
}
printf("/n");
}

int main()
{
Node *head;
DNode *root;
///////////////////////////单链表///////////////////////////////////////
printf("/toperate on single link list/n");
//create & print
printf("Create:node value with 3 * i (i is integer)/n");
head = sll_create(5);
sll_print(head);

//insert & print
printf("Insert node:/n");
sll_insert(&head,4);
printf("After inserting:");
sll_print(head);

//delete & print
printf("Delete node:");
sll_delete(&head,9);
printf("After deleting:");
sll_print(head);

////////////////////////////双链表////////////////////////////////////////

//create & print
printf("/n/toperate on double link list/n");
printf("Create:node value with 3 * i (i is integer)/n");
root = Dll_create(10);
Dll_print(root);

//insert & print
printf("Insert node:/n");
Dll_insert(root,4);
printf("After inserting:");
Dll_print(root);

//delete & print
printf("Delete node:/n");
Dll_delete(root,9);
printf("After deleting:");
Dll_print(root);

//search & print
printf("Search node:/n");
Dll_search(root,30) ? printf("value 30 exists in the list/n") : printf("value 30 doesn't exist in the list/n");

return 0;

}