C语言面试题分类->链表

链表的创建,清空,插入,删除

typedef int (* __compfunc)(const void *, const void *);

//Traverse list. Fast macro to traverse the list.
#define linklist_next(al) 
      ((al) && ((al)=(al)->next) ? (al)->data : NULL)

typedef struct linklist
{
  void *  data;
  struct linklist *  next;
} linklist_t;

//Allocate a new list data structure
linklist_t * linklist_create()
{
  linklist_t *ll;
  ll = (linklist_t *) calloc(1, sizeof(linklist_t));
  return ll;
}

//Destroy the list ll.
void linklist_destroy(linklist_t *ll)
{
  if (ll) {
    linklist_t *current = NULL;
    while ((current=ll)) {ll = ll->next; free(current);}
  }
}

//Insert an element at the tail of a list.
int linklist_add(linklist_t *ll, void *data)
{
  if (ll) {
    linklist_t *node = NULL;
    if ((node=(linklist_t *)calloc(1, sizeof(linklist_t))) == 0)
      return -1;
    while (ll->next) ll = ll->next;
    node->data = data;
    node->next = ll->next;
    ll->next = node;
    return 0;
  }
  return -1;
}

//Remove element from the list.
int linklist_remove(linklist_t *ll, void *data)
{
  if (ll) {
    linklist_t *prev = NULL;
    while (ll->next) {
      prev = ll;
      ll = ll->next;
      if (ll->data == data) {
        prev->next = ll->next;
        free(ll);
        return 0;/* Success */
      }
    }//while
  }
  return 1;  /* object not found or NULL list  */
}

// Do an insertion sort algorithm on the list. An empty list is already
// sorted and so is a single element list.
int linklist_insert(linklist_t *ll, void *data, __compfunc cbcomp)
{
  if (ll) {
    linklist_t *node=NULL, *prev=NULL;
    if (!cbcomp)
      return linklist_add(ll, data);
    if ((node=(linklist_t *)calloc(1, sizeof(linklist_t))) == 0)
      return -1;
    node->data = data;
    if (!ll->next) {
      ll->next = node;
      return 0;
    }
    for (prev=ll,ll=ll->next;  ll;  prev=ll,ll=ll->next) {
      if (cbcomp(data, ll->data) <= 0) {
        prev->next = node;
        node->next = ll;
        return 0;
      }
    }
    prev->next = node;
  }
  return 0;
}


4.链表的逆序

LinkNode* ReverseLink(LinkNode* head)
{
    LinkNode *prev=NULL, *next=NULL;
    while(head)
    {
        next = head->next;
        head->next = prev;
        prev = head;
        head = next;
    }

    return prev;
}