单链表、双链表、循环链表总结

1.单链表（为升序链表，value按升序排列）

#include <stdio.h>#include <malloc.h>typedef struct NODE{struct NODE *link;int value;} Node;//最好放在头文件中Node *sll_creat();int sll_length(Node *p);Node *sll_del(Node *head,int value);void sll_print(Node *head);Node *sll_insert(Node *head,int n);Node *sll_reverse(Node *head);int main(){Node *p;p=sll_creat();sll_print(p);p=sll_del(p,3);sll_print(p);p=sll_insert(p,4);sll_print(p);p=sll_reverse(p);sll_print(p);return 0;}Node *sll_creat(){int data;Node *p;Node *head;Node *new;Node *temp;//用来删除没用的headhead=(Node *)malloc(sizeof(Node));p=head;//head没有改变， 改变的是p， head用来返回printf("please input the values,end with EOF:\n");while(scanf("%d",&data)==1){new=(Node *)malloc(sizeof(Node));if(new==NULL){printf("malloc error!\n");return NULL;}new->value=data;p->link=new;p=new;}temp=head;head=head->link;//将第一个无用节点head去除,如何free掉?p->link=NULL;free(temp);//删除没用的head，防止内存泄露return head;}int sll_length(Node *p){int count=0;while(p->link!=NULL){count++;p=p->link;}count++;//由于尾节点的存在return count;}void sll_print(Node *head){int n;Node *p=head;n=sll_length(p);printf("there are %d records,they are:\n",n);while(p->link!=NULL){printf("%d\n",p->value);p=p->link;}printf("%d\n",p->value);}/**1.此函数缺点是只能删除第一个value出现的节点*2.此函数验证了在结构体中的value跟局部变量value不冲突*/Node *sll_del(Node *head,int value)//缺点，只能删除第一个value所在的节点{Node *p1,*p2;p1=head;while(value!=p1->value&&p1->link!=NULL)//遍历链表，找到需要删除的节点{p2=p1;p1=p1->link;}if(value==p1->value){if(p1==head)//单独处理头节点{head=p1->link;free(p1);}else{p2->link=p1->link;free(p1);}}else{if(p1->value==value)//单独处理尾节点{p2->link=NULL;free(p1);}elseprintf("can't find the value:%d",value);}return head;}/**此函数是在节点中的数字递增的前提下才起作用（即该链表要为有序链表，value按升序排列）**/Node *sll_insert(Node *head,int n){Node *p=head;Node *p_prev;Node *p0=(Node *)malloc(sizeof(Node));while(n>=p->value&&p->link!=NULL){p_prev=p;p=p->link;}if(p->value>n){if(p==head){p0->value=n;p0->link=head;head=p0;}else{p0->value=n;p_prev->link=p0;p0->link=p;}}else{p0->value=n;p->link=p0;p0->link=NULL;}return head;}Node *sll_reverse(Node *head){Node *p1;Node *p2;Node *p3;p1=head;p2=p1->link;if(p1==NULL){return head;}else if(p1->link==NULL){head=p1->link;head->link=p1;p1->link=NULL;}else{while(p2->link){p3=p2->link;p2->link=p1;p1=p2;p2=p3;}}p2->link=p1;head->link=NULL;head=p2;return head;}

2.双链表:（value升序）

#include <stdio.h>#include <malloc.h>typedef struct NODE{struct NODE*next;struct NODE*prev;intvalue;} Node;//不要忘了分号Node*dll_creat();voiddll_print(Node *head);int dll_length(Node *head);Node*dll_del(Node *head,int value);Node *dll_insert(Node *head,int n);int main(){Node *p=dll_creat();dll_print(p);p=dll_del(p,5);dll_print(p);p=dll_insert(p,6);dll_print(p);return 0;}Node *dll_creat(){Node *head;Node *p;Node *temp;Node *new;int value;printf("please input the values,end with eof:\n");head=(Node *)malloc(sizeof(Node));if(head==NULL){printf("malloc error!!!\n");return NULL;}p=head;while(scanf("%d",&value)==1){new=(Node *)malloc(sizeof(Node));if(new==NULL){printf("malloc error!!!\n");return NULL;}new->value=value;p->next=new;new->prev=p;p=new;}temp=head;head=head->next;head->prev=NULL;p->next=NULL;free(temp);return head;}int dll_length(Node *head){Node *p;int length=0;p=head;while(p->next!=NULL){p=p->next;length++;}length++;return length;}voiddll_print(Node *head){int n=dll_length(head);Node *p=head;printf("there are %d records,they are :\n",dll_length(p));while(p->next!=NULL){printf("%d\n",p->value);p=p->next;}printf("%d\n",p->value);}Node *dll_del(Node *head,int value){Node *p=head;while(p->value!=value&&p->next!=NULL){p=p->next;}if(p->next==NULL)//尾节点{if(p->value==value){p->prev->next=NULL;p->prev=NULL;free (p);}else printf("can't find %d\n",value);}if(p->value==value){if(p==head)//头节点{head=head->next;head->prev=NULL;free(p);}else//中间节点{p->prev->next=p->prev->next->next;p->next->prev=p->next->prev->prev;free (p);}}return head;}Node *dll_insert(Node *head,int n){Node *new;Node *p=head;while(p->value<n&&p->next!=NULL){p=p->next;}new=(Node*)malloc(sizeof(Node));if(new==NULL){printf("malloc error!!!\n");return NULL;}new->value=n;if(p->next==NULL)//尾节点{p->next=new;new->prev=p;new->next=NULL;}else if(p==head)//头节点{new->prev=NULL;new->next=p;p->prev=new;head=new;}else//中间节点{p->prev->next=new;new->prev=p->prev;new->next=p;p->prev=new;}return head;}