嵌入式-删除链表节点

删除链表节点可以分为三种：删除头节点，删除中间节点和删除尾节点

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

struct Test
{
  int data;
  struct Test * next;
};

printfLink(struct Test * head)
{
   while(head!=NULL)
   {
      printf("%d\n",head->data);
      head=head->next;
   }
   putchar('\n');
}

struct Test * InsertBeforeNode(struct Test *head,int data,struct Test * new)
{
    struct Test * p=head;
   if(p->data==data)
   {
     new->next=head;
     return new;
   }
    while(p->next!=NULL)
    {
       if(p->next->data==data)
       {
          new->next=p->next;
          p->next=new;
          printf("insert OK\n");
          return head;
       }
       p=p->next;
       printf("no insert\n");
    }
    return head;
}

void InsertAfterNode(struct Test *head,int data,struct Test *new)
{
    struct Test * p=head;
    while(p!=NULL)
    {
        if(p->data==data)
        {
           new->next=p->next;
           p->next=new;
        }
        p=p->next;
    }
}

struct Test * DeleteNode(struct Test *head,int data)
{
   struct Test * p=head;
   if(p->data==data)
   {
      head=head->next;
      free(p); 
      return head;
   }
   while(p->next!=NULL)
   {
      if(p->next->data==data)
      {
         p->next=p->next->next;
         return head;
      }
      p=p->next;
   }
   if(p->next==NULL)
   {
      if(p->data==data)
      {
         
      }
   }
   return head;
}


int main()
{
   struct Test *head=(struct Test *)malloc(sizeof(struct Test));
   head->data=1;
   struct Test new1={2,NULL};
   struct Test new2={3,NULL};
   struct Test new3={4,NULL};
   struct Test new4={5,NULL};
   printf("no insert:\n");
   printfLink(head);

   InsertAfterNode(head,1,&new1);
   InsertAfterNode(head,2,&new2);
   InsertAfterNode(head,3,&new3);
   printf("after insert 1,2,3:\n");
   printfLink(head);

   struct Test *hp1=InsertBeforeNode(head,2,&new4);
   printf("after insert 5:\n");
   printfLink(hp1);

   struct Test *hp2=DeleteNode(hp1,1);
   printf("after delete head Node\n");
   printfLink(hp2);

   printf("after delete Middle Node\n");
   struct Test *hp3=DeleteNode(hp2,2);
   printfLink(hp3);

   printf("after delete end Node\n");
   struct Test *hp4=DeleteNode(hp3,4);
   printfLink(hp4);
   return 0;
}

 

输出结果：

no insert:
1

after insert 1,2,3:
1
2
3
4

insert OK
after insert 5:
1
5
2
3
4

after delete head Node
5
2
3
4

after delete Middle Node
5
3
4

after delete end Node
5
3