C 链表排序问题

我正在尝试使用冒泡排序对链接列表进行排序。我也不能仅仅交换节点内的值。我一直在画画，试图在没有帮助的情况下自己解决问题，但我开始感到头痛，不明白为什么这样做行不通

void sort_ascending(struct node ** head){
  int x;
  struct node*temp;
  struct node*temp2;
  x = length(*head)+1;    //checks if more than one node is in the list
  if(x < 2){
    printf("1 or less\n");
    //free(temp);
    return;
  }
  printf("longer than 1\n");
  printf("%d %d\n", (*head)->val, (*head)->next->val);
  if((*head)->val > (*head)->next->val){
    printf("needs to sort!\n");
    temp = (*head)->next->next; //sets temp to the node after the two nodes being swapped
    printf("test1\n");
    temp2 = (*head); //sets temp2 to the node1
    printf("test2\n");
    *head = (*head)->next; //changes head to point at node2 instead of node1
    printf("test3\n");
    (*head)->next = temp2; //sets node2 to point to node1
    (*head)->next->next = temp; //sets node2 to point back into the list
    printf("test4\n");
    //free(temp);
  }
}

})

其他职能：

void push(struct node ** headRef, int data){
struct node* newNode =  malloc(sizeof(struct node)); //alocates space on heap
printf("pushed node\n");
newNode->val = data;//sets data value
printf("%d\n", newNode->val);
newNode->next = *headRef; // The '*' to dereferences back to the real head
*headRef = newNode; // ditto

})

}

}所以，让我们总结一下

函数长度被关闭1

int length(struct node* head){
    int length = 0;
    while (head != NULL){
        ++length;
        head = head->next;
    }
    return length;
}

打印功能打印太多

void print(struct node * head, int length){
    int x;
    for(x = 0; x < length; ++x){
        printf("%d\n", head->val);
        head = head->next;
    }
}

另外，如前所述，如果您使用C语言编程

---

如果你想知道为什么我把你的后缀+ +（比如<代码> x++<代码>）改为前缀++（比如<代码> ++x >）：我是C++程序员，对于C++，建议使用前缀+ +过后缀+ +，因为性能原因（与int或指针无关，但对于迭代器等复杂类型）。你如何测试它是否有效？在我创建了两个节点后，比如一个值为5，另一个值为6，我调用这个函数对我创建的节点进行排序。如果它能重新排列它们，我知道它能工作。我知道你了解排序的工作原理。：）我想知道1）您是如何构造节点的（向我们展示您的代码），以及2）您是在调试程序中检查值还是将值打印到屏幕上以测试其是否有效。@WernerHenze虽然您的malloc语句是真的，但OP确实声明他现在只尝试对前两个元素进行排序，稍后将添加循环。感谢malloc信息，我将删除它们。

int main(){
char ans;
int num;
struct node *head = NULL;
do {
    do {
        printf("Enter a number: ");
        scanf("%d", &num);
        push(&head, num);//Can change to append for back

        printf("Do you want another num (y or n): ");
        scanf("%1s", &ans);
    } while (ans == 'y');

    printf("Sort ascending or descending (a or d)? ");
    scanf("%1s", &ans);
    if(ans == 'a') sort_ascending(&head);
    //else if(ans == 'd') sort_descending(&head);

    print(head, length(head));

    printf("Do you want to do this again (y or n)? ");
    scanf("%1s", &ans);
    if (ans == 'y') clear(&head);

} while (ans == 'y');


return 0;

int length(struct node* head){
int length = 0;
//struct node*temp = head;
printf("tried to find length\n");
while (head->next != NULL){
    length++;
    head = head->next;
}
printf("%d\n", length + 1);
return length;

int length(struct node* head){
    int length = 0;
    while (head != NULL){
        ++length;
        head = head->next;
    }
    return length;
}

void print(struct node * head, int length){
    int x;
    for(x = 0; x < length; ++x){
        printf("%d\n", head->val);
        head = head->next;
    }
}

char ans;
scanf("%c", &ans);