删除附加在C中链接列表末尾的节点

I have a linked list where each node stores a word and a number. I can add nodes at the top of the list (push), at the center of the list (insertAfter) and at the end of the list (append). I now added a function to delete nodes, where it will take a char, it will search that char through the list and delete the node that stores that char.

我有一个链表，每个节点存储一个单词和一个数字。我可以在列表顶部（推送），列表中心（insertAfter）和列表末尾（追加）添加节点。我现在添加了一个删除节点的函数，它将获取一个char，它将通过列表搜索该char并删除存储该char的节点。

The problem is that deleteNode will work with a normal node added at the top of the list, but when i append a node at the end or add it at the middle of the list it won't work.

问题是deleteNode将使用添加在列表顶部的普通节点，但是当我在末尾添加节点或将其添加到列表的中间时，它将无法工作。

Tl;dr deleteNode works with nodes created with push but not with nodes created with append or insertAfter.

Tl; dr deleteNode与使用push创建的节点一起使用，但不与使用append或insertAfter创建的节点一起使用。

The error i get is segmentation fault, so i don't have a specific error from the compiler. I'm trying to debug it by running different parts of the code but i still can't find the problem.

我得到的错误是分段错误，所以我没有编译器的特定错误。我试图通过运行代码的不同部分来调试它，但我仍然找不到问题。

struct Node
{
  int data;
  char *word;
  struct Node *next;
};


void push(struct Node** head_ref, int new_data, char *new_word)
{
    struct Node* new_node = (struct Node*) malloc(sizeof(struct Node));

    new_node->data  = new_data;


    new_node->word= malloc(strlen(new_word));
    strcpy(new_node->word, new_word);

    new_node->next = (*head_ref);

    (*head_ref)    = new_node;
}

/* Given a node prev_node, insert a new node after the given 
   prev_node */
void insertAfter(struct Node* prev_node, int new_data, char *new_word)
{

    if (prev_node == NULL)
    {
      printf("the given previous node cannot be NULL");
      return;
    }

    struct Node* new_node =(struct Node*) malloc(sizeof(struct Node));

    new_node->data  = new_data;

    new_node->word= malloc(strlen(new_word));
    strcpy(new_node->word, new_word);

    new_node->next = prev_node->next;
    prev_node->next = new_node;
}


void append(struct Node** head_ref, int new_data, char *new_word)
{

    struct Node* new_node = (struct Node*) malloc(sizeof(struct Node));

    struct Node *last = *head_ref;  


    new_node->data  = new_data;

    new_node->word= malloc(strlen(new_word));
    strcpy(new_node->word, new_word);

    new_node->next = NULL;


    if (*head_ref == NULL)
    {
       *head_ref = new_node;
       return;
    }


    while (last->next != NULL)
        last = last->next;


    last->next = new_node;
    return;
}



void deleteNode(struct Node **head_ref, char *word)
{

    struct Node* temp = *head_ref, *prev;
    if (strcmp(word, (*head_ref)->word)==0)
    {
        *head_ref = temp->next;   // Changed head
        free(temp);               // free old head
        return;
    }



    while (strcmp(word, (*head_ref)->word)!=0)
    {
        prev = temp;
        temp = temp->next;
    }

    if (temp == NULL) return;


    prev->next = temp->next;

    free(temp);  // Free memory

}

2 个解决方案

#1

This part looks strange:

这部分看起来很奇怪：

while (strcmp(word, (*head_ref)->word)!=0)
{
    prev = temp;
    temp = temp->next;
}

In the strcmp you use head_ref but in the body you update temp to move to the next element.

在strcmp中你使用head_ref，但在正文中你更新temp以移动到下一个元素。

Did you intend to do:

你有意这样做：

while (strcmp(word, temp->word)!=0)
{
    prev = temp;
    temp = temp->next;
}

Further there should probably some check for temp being NULL. Like:

此外，应该检查temp为NULL。喜欢：

while (temp && strcmp(word, temp->word)!=0)

#2

Apart from what was stated by @4386427, you are not allocating enough space for your strings there:

除了@ 4386427所说的，你没有为你的字符串分配足够的空间：

new_node->word= malloc(strlen(new_word));

Notice that the C library function size_t strlen(const char *str) computes the length of the string str up to, but not including the terminating null character. So i would rather suggest:

请注意，C库函数size_t strlen（const char * str）计算字符串str的长度，但不包括终止空字符。所以我宁愿建议：

new_node->word= malloc(strlen(new_word) + 1);
new_node->word[strlen(new_word)] = '\0';

This can cause you some problems with the memory. ;)

这可能会导致内存出现问题。 ;）

Or event better, use calloc, so the second line will be unnecessary:

或事件更好，使用calloc，所以第二行将是不必要的：

new_node->word= calloc(strlen(new_word) + 1, sizeof(char));

#1