C++ 实现简单字典时C语言中的段错误

因此，我try 实现了一个简单的词典，如这post中所示.但是，我确实修改了代码:

A)词典:

/* String utility for duplication */
char *strdup(char *s) /* make a duplicate of s */
{
    char *p;
    p = (char *) malloc(strlen(s)+1); /* +1 for ’\0’ */
    if (p != NULL)
       strcpy(p, s);
    return p;
}

struct nlist {
    struct nlist *next;
    char *name;
    char *defn;
};

#define HASHSIZE 101
struct Dict {
    struct nlist *hashtab[HASHSIZE];
};

/* hash: form hash value for string s */
unsigned hash(char *s)
{
    unsigned hashval;
    for (hashval = 0; *s != '\0'; s++)
      hashval = *s + 31 * hashval;
    return hashval % HASHSIZE;
}

/* lookup: look for s in hashtab */
struct nlist *lookup(struct Dict *d, char *s)
{
    struct nlist *np;
    for (np = d->hashtab[hash(s)]; np != NULL; np = np->next)
        if (strcmp(s, np->name) == 0)
          return np; /* found */
    return NULL; /* not found */
}

struct nlist *insert(struct Dict *d, char *name, char *defn)
{
    struct nlist *np;
    unsigned hashval;
    if ((np = lookup(d, name)) == NULL) { /* not found */
        np = (struct nlist *) malloc(sizeof(*np));
        if (np == NULL || (np->name = strdup(name)) == NULL)
          return NULL;
        hashval = hash(name);
        np->next = d->hashtab[hashval];
        d->hashtab[hashval] = np;
    } else /* already there */
        free((void *) np->defn); /*free previous defn */
    if ((np->defn = strdup(defn)) == NULL)
       return NULL;
    return np;
}

B)示例:

int main() {
    struct Dict *dtest = (struct Dict*)malloc(sizeof(struct Dict));
    insert(dtest, "hello", "world");
    // Look up a definition by name
    struct nlist *result = lookup(dtest, "hello");
    
    if (result != NULL) {
        printf("Definition for 'hello': %s\n", result->defn);
    } else {
        printf("'hello' is not found in the dictionary.\n");
    }

    return 0;
}

当我try 调试它时，收到以下错误:

线程%1收到信号SIGSEGV，分段故障. 正在查找中的0x00007ff6bc661626(d=0x220924616e0，S=0x7ff6bc673006"Hello").c:40 40if(strcMP(S，NP-&>名称)==0)

我只是不明白简单的代码修改怎么会产生这种意想不到的行为，坦率地说，我也不确定如何go 做.