c 中的嵌套结构和链表 - 分段错误

Question

I have a set of structures which I need to use to make a linked list like so:

typedef struct {         
 int tm_min;
 int tm_hour;
} event_time_t;

typedef struct {          
 int tm_mday;
 int tm_mon;
 int tm_year;
} event_date_t;

typedef struct event_t {          
 char title[20];         
 event_time_t *time;
 event_date_t *date;
 struct event_t *next;
} event_t;

This is my function that is supposed to add new nodes to the list every time it's called:

void add_events(void) {
  event_t *new_node = NULL;
  event_t *temp_node = NULL;

  new_node = (event_t*) malloc(sizeof(event_t)); /*allocate memory to the node*/
  new_node->time = (event_time_t*) malloc(sizeof(event_time_t));
  new_node->date = (event_date_t*) malloc(sizeof(event_date_t));
  new_node->next = NULL;

  scanf("%s", &head_node->title); /*assign values to the node from the user*/
  scanf("%d", &head_node->time->tm_hour);
  scanf("%d", &head_node->time->tm_min);
  scanf("%d", &head_node->date->tm_mon);
  scanf("%d", &head_node->date->tm_mday);
  scanf("%d", &head_node->date->tm_year);

  if (head_node == NULL) { /*if there is only a head node, set it equal to new_node*/
    head_node = new_node;
  }
  else {
    temp_node = head_node;
    while (temp_node->next != NULL) { /*find the latest linked node*/
      temp_node = temp_node->next;
    }
    temp_node->next = new_node; /*link the new node to the latest node*/
  }


}

The head_node is declared globally as event_t *head_node = NULL . However, every time I call this function in GCC I run into a segmentation error and can't resolve it. Please help.

Answer 1

You are writing to head_node with your scan_f calls. Those should be writing to new_node .