单链表建立、插入、逆序

//建立数据
typedef struct student
{
int data;
struct student * next;
}node;

//建立单链表
node * create()
{
node *head,*p,*s;
int x,cycle=1;

head = (node *)malloc( sizeof(node) );
p=head;

while(cycle)
{
//读入数据
printf("Please input the data:\n");
scanf("%d",&x);

if(x!=0)
{
s=(node *)malloc( sizeof(node) );
s->data=x;

p->next=s;
p=s;
}
else   cycle=0;
}

p->next = NULL;
head=head->next;

return head;
}

node * reverse(node * head)

{

node *p1, *p2, *p3;

if(head==NULL || head->next==NULL)

return head;

p1=head;

p2=p1->next;

while(p2)

{

p2->next = p3;

p2->next = p1;

p1=p2;

p2=p3;

}

head->next=NULL;

head = p1;

return head;

}

//单链表插入有序链表，不改变链表原有顺序

node * insert(node *head, int num)

{

node *p0, *p1, *p2;

p0=(node *)malloc(sizeof(node));

p0->data=num;

p1=head;

while(num>p1->data && p1->next!=NULL)

{ p2=p1;p1=p1->next;}

if(p1->data>=num)

{ if(p1==head)

{

p0->next = head;

head = p0;

 }

else

   {

p2->next=p0;

p0->next=p1;

}

 }

else

  {p1->next=p0;

p0->next = NULL;

  }

return head;

}

//单链表删除

node * del(node *head, int num)

{

node *p1,*p2;

  p1=head;

while(p1!=NULL && num!=p1->data)

  {p2=p1;p1=p1->next;}

if(p1==NULL)

  printf("没找到");

 elseif(p1==head)

  head=head->next;

else

   {

   p2->next=p1->next;

}

return head;

}