我想要做的是交换单向链表的第一个和最后一个元素。到目前为止，我有以下代码，我在其中创建了一个列表并向其中添加了一些数字。我的问题出在 swapElements1 函数上。

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

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

void addNodeSingle(struct node **head, int num, int thesi) //Function to insert new node at the beginning or the end of the list, depending on the value of "thesi"
{
    if (*head == NULL)
    {
        struct node *current;
        current = (struct node*) malloc (1*sizeof(struct node));
        current -> number = num;
        current -> next = NULL;
        *head = current;
    }

    else
    {
        if (thesi == 0)
        {
            struct node *current;
            current = (struct node*) malloc (1*sizeof(struct node));
            current -> number = num;
            current -> next = *head;
            *head = current;
        }

        else
        {
            struct node *current, *temp;
            current = (struct node*) malloc (1*sizeof(struct node));
            current -> number = num;
            temp = *head;
            while (temp -> next != NULL)
                temp = temp -> next;

            temp -> next = current;
            current -> next = NULL;
        }
    }
}

void displayList(struct node **head) //Function to display the list
{
    struct node *current;
    if(*head == NULL)
        printf("I lista einai adeia!\n");

    else
    {
    current= *head ;
        while(current != NULL)
        {
            printf("%d ",current -> number);
            current = current -> next;
        }
    }
}

void swapElements1(struct node **head) //(not working)Function to swap first and last element of the list
{
    struct node *current, *temp;
    current = temp = *head;

    while(current != NULL)
    {
        temp = current;
        current = current -> next;
    }

    *head = (*head)->next;
    *head = temp;
    current = NULL;
}

int main()
{
    struct node *head;
    head = NULL;

    addNodeSingle(&head,5,1);
    addNodeSingle(&head,6,1);
    addNodeSingle(&head,2,0);
    addNodeSingle(&head,7,0);
    addNodeSingle(&head,8,0);

    printf("List is: ");
    displayList(&head);
    swapElements1(&head);
    printf("\nNew list is: ");
    displayList(&head);
}

我得到的输出是：

列表为：8 7 2 5 6

新名单是：6

我需要的是：

列表为：8 7 2 5 6

新列表是：6 7 2 5 8

这是一个演示