添加到节点时如何重置指向头节点的指针？

Question

我需要从每个周期的头节点开始，将新节点添加到正确的位置。我认为我当前的代码使 head 和 sptr 的指针相等，所以当我移动一个时，另一个也会移动。如何将指针 sptr 移动到开头？

在调试器中，当我按原样将 "a" 保存为单词时，head->letter[1] 变为真，但稍后 sptr = head; 运行后立即变回假。我认为这与指针有关。

typedef struct node
{
    bool exist;
    struct node* letter[28];
} trie;

trie *head = NULL;
int words = 0;

// Loads dictionary into memory, returning true if successful else false
bool load(const char *dictionary)
{
    int i = 0;

    FILE *infile = fopen(dictionary, "r");
    if (infile == NULL)
    {
        printf("Could not open %s.\n", dictionary);
        return 1;
    }
    // allocate memory
    head = calloc(sizeof(trie), 1);
    head->exist = false;
    trie *sptr = head;
    int cr;

    // loop through file one character at a time
    while ((cr = fgetc(infile)) != EOF)
    {
        // build a trie
        // check if it's end of line
        if (cr != 10)
        {
            i = tolower(cr) - 96;
            // check for apostrophy
            if (i < 0)
            {
                i = 0;
            }
            // check if the position exists
            if (sptr->letter[i] == NULL)
            {
                sptr->letter[i] = malloc(sizeof(trie));
                sptr->exist = false; // not the end of the word
            }
            sptr = sptr->letter[i];
        }
        else // indicate the end of a word that exists
        {
            sptr->exist = true;
            sptr = head;// I think the problem might be here, I'm trying to move the pointer to the beginning.
            words++;
        }
    }

    return true;
}

Answer 1

找到问题了。它在 sptr->exist = false 行中，应该是 sptr->letter[i]->exist = false。指针移动正常，但我正在更改当前指针所在位置的值，而不是新创建的节点。

添加到节点时如何重置指向头节点的指针？

How do I reset the pointer to the head node when adding to nodes?

c

trie