c - 删除和 DFS 功能无法正常工作

Question

我正在尝试创建一个树数据结构来存储有关奥运场馆的信息。我刚刚遇到了障碍，我意识到我的删除函数总是返回“Element Not Found”，并且我的 DFS 将找到正确的节点，但然后继续打印出树的右侧。

Tree * preorder_find(char * find_city, Tree* T)
{
    if(T)
    {

        //if(strcmp(T->Element->city, find_city) == 0)
        //return T;

        printf("%s, %s ... %d\n", T->Element->city, T->Element->country, 
                                                T->Element->year);

        if(strcmp(T->Element->city, find_city) != 0)
        {   
            preorder_find(find_city, T->Left);

            preorder_find(find_city, T->Right);
        }

    }


return T;

}



Tree* delete(char * venue, Tree* T)
{
    Tree* tmp_node;

    if(T==NULL)
        fprintf(stderr, "Element not Found\n");
    else
    if(strcmp(venue, T->Element->city) < 0)
        T->Left = delete(venue, T->Left);
    else
    if(strcmp(venue, T->Element->city) > 0)
        T->Right = delete(venue, T->Left);
    else
    if(T->Left && T->Right)
    {
        tmp_node = find_min(T->Right);
        T->Element = tmp_node->Element;
        T->Right = delete(T->Element->city, T->Right);
    }
    else
    {
        tmp_node = T;
        if(T->Left == NULL)
            T = T->Right;
        else if(T->Right == NULL)
            T = T->Left;
        free(tmp_node);
     }

     return T;
}

Answer 1

1. 请尝试这个preorder_find()

   Tree * preorder_find(char * find_city, Tree* T) { 树*温度；

   if(T)
   {
   
       if(strcmp(T->Element->city, find_city) == 0)
           return T;
   
       printf("%s, %s ... %d\n", T->Element->city, T->Element->country, 
               T->Element->year);
   
       if(strcmp(T->Element->city, find_city) != 0)
       {   
           if ((temp = preorder_find(find_city, T->Left))
                   || (temp = preorder_find(find_city, T->Right)))
               return temp;
       }
   
   }
   
   
   return T;
   

   }

2. my delete function always returns "Element Not Found"

   根据您的delete()，这意味着delete()的参数T始终为NULL .