在C中,如何访问此结构中的元素？

Question

如果我按如下方式初始化列表,如何访问此结构中的元素:

group **list = (group **) malloc(sizeof(group)); 

typedef struct
{
    // ID of the group, 'A' to 'D'
    char id;

    // a list of members in the group 
    char **members;
} group;

我尝试使用(*list)->id = 'A'并编译,但在运行程序时出现分段错误错误.

Answer 1

struct group
{
    // ID of the group, 'A' to 'D'
    char id;

    // a list of members in the group 
    char **members;
};

//this initializes one group
group *a_group = malloc(sizeof(struct group)); //cast not needed in C

//this initializes an array of 10 group
group **list = malloc(sizeof(struct group *) * 10);

//initialize each one of the 10
for(int i = 0; i < 10; ++i){
  list[i] = malloc(sizeof(struct group));
}

//get something out of group
a_group->id;

//get first group out of list
list[0]->id;
*list->id;

// 10 elements continuous memory
group *array_of_groups = malloc(sizeof(struct group) * 10);
array_of_groups[0].id;
*array_of_groups.id;