删除链表中的随机节点

Question

I wrote this code to delete any item from the linked list,

this is the output after insertion
 16 -->  15 -->  14 -->  13 -->  12 -->  11 --> 

when i delete 11 the output is like this
16 -->  15 -->  14 -->  13 -->  12 -->  0 --> 

how to remove that zero at the last?

typedef struct node
{
int data;
struct node *next;
}node;

node *getnode()
{
node *x;
x = (node*)malloc(sizeof(node));
if (x==NULL)
    {
        printf("no memory \n");
        exit(1);
    }
return x;
}

node *insert_front(int item , node *first)
{

node *temp;
temp = first;

temp = getnode();
temp -> data = item;
temp -> next = first;
return temp;
}

void *display(node *first)
{
node *temp;
temp = first;
if (temp == NULL)
    {
        printf("list is empty \n");
        return ;
    }
while (temp != NULL)

    {
        printf(" %d --> ",temp -> data);
        temp = temp -> next;

    }
}


void delete_middle(int item, node *first)
{
node *temp;
node *store_addr;
int value;
temp = first;
if (temp == NULL)
{
   printf("list is empty \n");
   return ;
}

while(temp!=NULL)
{
if (temp->data == item)
{
    if(temp->next != NULL)
    {
    temp->data =  temp->next->data;
            temp->next = temp->next->next;
    }
    else
     free(temp); 
    break;
}
temp = temp->next;
}


}


main()
{

node *first;
int item = 11,ch,i;
first = NULL;
while(1)
{
    printf("\n 1.insert front \n 2.display \n 3. delete middle \n 4.quit\n");
            scanf ("%d",&ch);
    switch(ch)
    {

    case 1:  // printf("\nenter the item to be inserted \n");
          //scanf("%d",&item);
           for(i=0 ;i<6;i++)
          first = insert_front (item++ , first);
          break;

    case 2:   display(first);
          break;


    case 3 :  printf("delete in middle \n");
          scanf("%d",&item);
          delete_middle(item, first);
          break;

    case 4:   exit(0);
          break;
}
}
}

Answer 1

While deleting, you must store the previous node in the list and modify it. For example, you can handle the first node separately and loop like this

struct node* tmp;    
while(temp->next!=NULL)
{
    if (temp->next->data == item)
    {
        tmp = temp->next->next;
        free(temp->next); 
        temp->next = tmp;
    }
    temp = temp->next;
}

In your code, you free(temp) if it is the last one, but you don't remove it from the list. This makes the list corrupted and can lead to many bad behaviour of your software. NEVER keep a reference to a freed pointer.

Answer 2

In your code try this,

while(temp!=NULL)
{
   if (temp->data == item)
   {
        if(temp->next != NULL)
        {
            prev->next = temp->next;
        }

        free(temp);
        break; 
   } 
   prev = temp;
   temp = temp->next; 
 }