c - Level traversing to print a BST using array of pointers. -

i'm trying traverse level level through tree print it. instead of creating copy of tree, need use dynamic array of pointers tree. it's been 4 hours i'm beginner , couldn't put finger on reason behind segmentation fault. apologise if bug kind of easy spot or if not worth posting:

typedef struct bst{     int value;      struct bst* right;      struct bst* left;  }bstn;                //binary search tree node  //prototype:  int height(bstn* b); void insert(bstn** root, int value);  void print(bstn* b);   void print(bstn* b){     bstn** level_pointers =  (bstn**)malloc( sizeof(bstn*));     level_pointers[0] = b;                 //copy of pointer root     int level_pointers_len = 1;    //initial length of array of pointers     int new_level_index;                                         int new_level_len;     bstn** new_level = (bstn**) malloc(2*level_pointers_len* sizeof(bstn*));       //each new level max twice previous      while(1){          new_level_index = 0;          (int = 0; < level_pointers_len; i++){             printf("%i \t", level_pointers[i]->value);               if (level_pointers[i]->left != null){                 new_level[new_level_index] = level_pointers[i]->left;                  new_level_index ++;              }             if (level_pointers[i]->right != null){                 new_level[new_level_index] = level_pointers[i]->right;                  new_level_index ++;              }          printf("\n");          }         if (new_level_index == 0)              return;          new_level_len = new_level_index + 1;          level_pointers = (bstn**)realloc(new_level, new_level_len*sizeof(bstn*));          new_level = (bstn**) malloc(2*level_pointers_len* sizeof(bstn*));          level_pointers_len = new_level_len;      }    }