在结构时间内访问结构3？

Question

我在C中有一个作业，我在访问我的结构中的不同成员时遇到了问题（某些级别很深）。我理解基本原则，但我有点失去它。我有3个结构，顶部的一个包含第二个数组，而第二个包含第三个数组。我目前的问题是使用malloc正确的方法。这是我的一些代码。我会很感激任何信息或提示，因为我还有很长的路要走，因为你可以看到结构有点复杂。

.h文件

typedef struct user {
    char* userID;
    int wallet;
    bitCoinList userBC; //Also a list
    senderTransList userSendList; //Yes it has lists too..
    receiverTransList userReceiveList;
}user;

typedef struct bucket {
    struct bucket* next;
    user** users;
}bucket;

typedef struct hashtable {
    unsigned int hashSize;
    unsigned int bucketSize;
    bucket** buckets;
}hashtable;

这是我创建和初始化哈希表的函数。当我尝试使用HT->buckets->users访问用户时遇到错误（请求成员用户不是结构或联合）

.c文件

// Creation and Initialization of HashTable
hashtable* createInit(unsigned int HTSize,unsigned int buckSize){

    hashtable* HT = (hashtable*)malloc(sizeof(hashtable));
    if(HT==NULL) {
        printf("Error in hashtable memory allocation... \n");
        return NULL;
    }

    HT->hashSize=HTSize;
    HT->bucketSize=buckSize;

    HT->buckets = malloc(HTSize * sizeof(HT->buckets));
    if(HT->buckets==NULL) {
        printf("Error in Buckets memory allocation... \n");
        return NULL;
    }
    HT->buckets->users = malloc(buckSize * sizeof(HT->buckets->users));
    if(HT->buckets->users==NULL) {
        printf("Error in Users memory allocation... \n");
        return NULL;
    }
    for(int i=0; i <HTSize; i++){
        HT->buckets[i] = malloc(sizeof(bucket));
        HT->buckets[i]->next = NULL;
        if(HT->buckets[i]==NULL) {
            printf("Error in Bucket %d memory allocation... \n",i);
            return NULL;
        }

        for(int j=0; j <buckSize; j++){
            HT->buckets[i]->users[j] = malloc(sizeof(user));
            if(HT->buckets[i]==NULL) {
                printf("Error in User %d memory allocation... \n",i);
                return NULL;
            }
        }
    }
    return HT;
}

Answer 1

因为存储桶是指针类型的指针，您需要：

(*(HT-> buckets)) ->users = ....

要么

HT-> buckets[0] ->users = ....   // or any other index depending of the program logic

或（对于第n个指针）

(*(HT-> buckets + n)) ->users = ....

要么

HT-> buckets[n] ->users = ....   // or any other index depending of the program logic

This only the syntax answer and I do not analyze the program logic

Answer 2

至少有一个问题：错误的大小分配。

分配给HT->buckets指向的数据的大小，而不是指针的大小。

避免错误。以下成语易于编码，审查和维护。

ptr = malloc(sizeof *ptr * n);

---

// HT->buckets = malloc(HTSize * sizeof(HT->buckets));
HT->buckets = malloc(HTSize * sizeof *(HT->buckets));

// HT->buckets->users = malloc(buckSize * sizeof(HT->buckets->users));
HT->buckets->users = malloc(buckSize * sizeof *(HT->buckets->users));

// HT->buckets[i] = malloc(sizeof(bucket));
HT->buckets[i] = malloc(sizeof *(HT->buckets[i]));

// HT->buckets[i]->users[j] = malloc(sizeof(user));
HT->buckets[i]->users[j] = malloc(sizeof *(HT->buckets[i]->users[j]));