c - 向 HashTable 插入时出错

Question

当尝试在哈希表中插入字符串时，即使哈希函数计算的位置是有效的，我也会收到段错误错误。

#define initial_size 23

typedef struct user{
    char nick[6];
    char name[26];
}user;

typedef struct hashtable{
    int size;
    user **buckets;
}hashtable;

int elements = 0;
int size = initial_size;

hashtable * create() {
    hashtable *htable = malloc(sizeof(htable));
    htable->size = initial_size;
    htable->buckets = calloc(initial_size, sizeof(htable->buckets));
    return htable;
}

int hash(char *string) {
    int hashVal = 0;
    for( int i = 0; i < strlen(string);i++){
        hashVal += (int)string[i];
    }
    return hashVal;
}


void insert(hashtable *HashTable, char *name, char *nick){
    HashTable = resize_HashTable(HashTable);
    int hash_value = hash(nick);
    int new_position = hash_value % HashTable->size;
    if (new_position < 0) new_position += HashTable->size;
    int position = new_position;
    while (HashTable->buckets[position] != 0 && position != new_position - 1) {
        position++;
        position %= HashTable->size;
    }
    strcpy(HashTable->buckets[position]->name, name);
    strcpy(HashTable->buckets[position]->nick, nick);
    HashTable->size = HashTable->size++;
    elements++;
}

错误在这几行:

strcpy(HashTable->buckets[position]->name, name);
strcpy(HashTable->buckets[position]->nick, nick);

使用此输入时:

int main(){
    hashtable *ht = create();
    insert(ht, "James Bond", "zero7");
    return 0;
}

我无法理解为什么会发生这种情况，因为在上面的情况下，计算出的哈希位置将为 20，而哈希表的大小将为 23。

有什么解决问题的技巧吗？提前致谢。

Answer 1

您应该在 create() 函数中为每个存储桶分配内存。

hashtable * create() {
hashtable *htable = malloc(sizeof(htable));
htable->size = initial_size;
htable->buckets = calloc(initial_size, sizeof(htable->buckets));
int i;
for(i=0;i<initial_size;i++)
    htable->buckets[i] = (user*)malloc(sizeof(user));
return htable;
}