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📜  用于删除给定位置的链表节点的 C 程序

📅  最后修改于: 2022-05-13 01:54:58.806000             🧑  作者: Mango

用于删除给定位置的链表节点的 C 程序

给定一个单链表和一个位置,删除给定位置的链表节点。

例子:

Input: position = 1, Linked List = 8->2->3->1->7
Output: Linked List =  8->3->1->7

Input: position = 0, Linked List = 8->2->3->1->7
Output: Linked List = 2->3->1->7

如果要删除的节点是根节点,直接删除即可。要删除中间节点,我们必须有一个指向要删除的节点之前的节点的指针。因此,如果位置不为零,我们运行一个循环位置 1 次并获得指向前一个节点的指针。

下面是上述思想的实现。

C
// A complete working C program to delete a node in a linked list
// at a given position
#include 
#include 
  
// A linked list node
struct Node
{
    int data;
    struct Node *next;
};
  
/* Given a reference (pointer to pointer) to the head of a list
   and an int inserts a new node on the front of the list. */
void push(struct Node** head_ref, int new_data)
{
    struct Node* new_node = (struct Node*) malloc(sizeof(struct Node));
    new_node->data  = new_data;
    new_node->next = (*head_ref);
    (*head_ref)    = new_node;
}
  
/* Given a reference (pointer to pointer) to the head of a list
   and a position, deletes the node at the given position */
void deleteNode(struct Node **head_ref, int position)
{
   // If linked list is empty
   if (*head_ref == NULL)
      return;
  
   // Store head node
   struct Node* temp = *head_ref;
  
    // If head needs to be removed
    if (position == 0)
    {
        *head_ref = temp->next;   // Change head
        free(temp);               // free old head
        return;
    }
  
    // Find previous node of the node to be deleted
    for (int i=0; temp!=NULL && inext;
  
    // If position is more than number of nodes
    if (temp == NULL || temp->next == NULL)
         return;
  
    // Node temp->next is the node to be deleted
    // Store pointer to the next of node to be deleted
    struct Node *next = temp->next->next;
  
    // Unlink the node from linked list
    free(temp->next);  // Free memory
  
    temp->next = next;  // Unlink the deleted node from list
}
  
// This function prints contents of linked list starting from
// the given node
void printList(struct Node *node)
{
    while (node != NULL)
    {
        printf(" %d ", node->data);
        node = node->next;
    }
}
  
/* Driver program to test above functions*/
int main()
{
    /* Start with the empty list */
    struct Node* head = NULL;
  
    push(&head, 7);
    push(&head, 1);
    push(&head, 3);
    push(&head, 2);
    push(&head, 8);
  
    puts("Created Linked List: ");
    printList(head);
    deleteNode(&head, 4);
    puts("
Linked List after Deletion at position 4: ");
    printList(head);
    return 0;
}


输出:

Created Linked List: 
 8  2  3  1  7 
Linked List after Deletion at position 4: 
 8  2  3  1 

有关详细信息,请参阅有关在给定位置删除链接列表节点的完整文章!