不带表头结点的非循环单向链表

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

struct node
{
int num;
struct node *next;
};

typedef struct node Node;
typedef struct node * Link;

void create_link(Link *head)
{
*head = NULL;
}

void insert_node_head(Link *head,Link new_node)
{
new_node->next = *head;
*head = new_node;
}

void display_node(Link head)
{
Link tmp;
tmp = head;
if(NULL == head)
{
printf("link is empty!\n");
return;
}

while(tmp != NULL)
{
printf("num = %d\n",tmp->num);
tmp = tmp->next;
}
}

void is_malloc_ok(Link new_node)
{
if(new_node == NULL)
{
printf("malloc error!\n");
exit(-1);
}
}

void create_newnode(Link * new_node)
{
*new_node = (Link)malloc(sizeof(Node));
is_malloc_ok(*new_node);
}

void insert_node_tail(Link *head,Link new_node)
{
Link tmp;

tmp = *head;

if(*head == NULL)
{
new_node->next = *head;
*head = new_node;
}
else
{
while(tmp->next != NULL)
{
tmp = tmp->next;
}
tmp->next = new_node;
new_node->next = NULL;
}
}

/*void insert_node_mid(Link *head,Link new_node,int num)
{
Link tmp;
tmp = *head;

if(NULL == *head)
{
printf("link is empty!\n");
return;
}
else
{
while(tmp->num != num && tmp->next != NULL)
{
tmp = tmp->next;
}
if(tmp->num == num)
{
new_node->next = tmp->next;
tmp->next = new_node;
}
else
{
printf("no such node!\n");
}
}

}*/

void delete_node(Link *head,int num)
{
Link tmp;
Link p;
tmp = p = *head;

if(NULL == *head)
{
printf("link is empty!\n");
return;
}

while(tmp->num != num && tmp->next != NULL)
{
p = tmp;
tmp = tmp->next;
}

if(tmp->num == num)
{
if(tmp == *head)
{
*head = tmp->next;
free(tmp);
}
else
{
p->next = tmp->next;
free(tmp);
}
}
else
{
printf("no such node!\n");
}
}

void release(Link *head)
{
Link tmp;

tmp = *head;

/*while (tmp != NULL)
{
*head = tmp->next;
free(tmp);
tmp = tmp->next;
}*/
while(tmp != NULL)
{
*head = (*head)->next;
free(tmp);
tmp = *head;
}
}
void insert_node_mid(Link *head,Link new_node,int num)
{
Link tmp;
Link p;

tmp = *head;
p = *head;

if(NULL == *head)
{
new_node->next = *head;
*head = new_node;
}
else
{
while((num > tmp->num) &&(tmp->next != NULL))
{
p = tmp;
tmp = tmp->next;
}
if(num <= tmp->num)
{
if(tmp == *head)
{
new_node->next = tmp;
*head = new_node;
}
else
{
p->next = new_node;
new_node->next = tmp;
}

}
if((num > tmp->num)&&(tmp->next == NULL))
{
tmp->next = new_node;
new_node->next = NULL;
}
}
}
void reverse_link(Link *head)
{
Link p1 = NULL;
Link p2 = NULL;
Link p3 = NULL;

if(NULL == *head || (*head)->next == NULL)
{
printf("No need reverse!\n");
return;
}
else
{
p3 = *head;
p2 = p3->next;
if(p2->next == NULL)
{
p2->next = p3;
p3->next = NULL;
*head = p2;
return;
}
p1 = p2->next;
p3->next = NULL;
while(p1->next != NULL)
{
p2->next = p3;
p3 = p2;
p2 = p1;
p1= p1->next;
}
p2->next = p3;
p1->next = p2;
*head = p1;
}
}

int main()
{
Link head = NULL;
Link new_node = NULL;
int i;
//int num;

create_link(&head);
//printf("Enter 10 number!\n");
for(i = 0; i < 10;i++)
{
create_newnode(&new_node);
new_node->num = i;
//scanf("%d",&(new_node->num));
insert_node_mid(&head,new_node,new_node->num);
//insert_node_head(&head,new_node);
//insert_node_tail(&head,new_node);
}

//printf("please input a num!\n");
//scanf("%d",&num);

//	create_newnode(&new_node);
//	new_node->num =  num;

//	insert_node_mid(&head,new_node,10);

//	delete_node(&head,num);

display_node(head);

//release(&head);

reverse_link(&head);

display_node(head);

return 0;
}