字符串的BST中的分段错误

Question

So, I'm doing an assignment for a class in college and the objective is to construct a BST of strings that read a text, divides it and insert each word in the Tree.

But I'm getting a segmentation fault when trying to insert a word (manually), can you guys show me where I did wrong and suggest a repair?

/* Structure for the node */
typedef struct node {
  char *key;
  int multi;
  struct node *left, *right;
} node;

node *root;

void Insert(char *x, node *p){
    p = root;

  /* if the pointer points to null, create a new node and insert the key */
  if (*p == NULL){
    (*p) = (node)malloc(sizeof(node))
    (*p)->key = strcpy((*p)->key, x);
    (*p)->left = NULL;
    (*p)->right = NULL;
    return;
  }
  else if (strcasecmp(x, p->key) < 0)
  { 
    Insert(x, &p->left);
    return;
  }

  else if (strcasecmp(x, p->key) > 0)
  {
    Insert(x, &p->right);
    return;
  }
  /* if the words are equal, add 1 to the multi (how many times the word appears */
  else
    (*p)->multi = multi + 1;
}

Answer 1

This is the problematic statement: (*p)->key = strcpy((*p)->key, x); You allocated memory only for node but the pointer key is still uninitialized. You need to allocate memory for key also, something like (*p)->key = malloc(strlen(x) + 1); .