RecursiveFree 函数 - 警告：从不兼容的指针类型初始化 [-Wincompatible-pointer-types]

Question

我有一个递归释放的函数：

#include "treeStructure.h"

void destroyTree (Node* p)
{
    if (p==NULL)
        return;
    Node* free_next = p -> child; //getting the address of the following item before p is freed
    free (p); //freeing p
    destroyTree(free_next); //calling clone of the function to recursively free the next item
}

treeStructure.h:

struct qnode {
  int level;
  double xy[2];
  struct qnode *child[4];
};
typedef struct qnode Node;

我一直收到错误消息

Warning: initialization from incompatible pointer type [-Wincompatible-pointer-types]

及其指向 'p'。

我不明白为什么会这样。

有人可以解释并告诉我如何解决这个问题吗？

Answer 1

您收到错误消息是因为指向 Node (child) 数组的指针无法转换为指向 Node (p) 的指针。

由于 child 是指向 Node 的四个指针的数组，因此您必须单独释放它们：

void destroyTree (Node* p)
{
    if (!p) return;

    for (size_t i = 0; i < 4; ++i)
        destroyTree(p->child[i]);

    free(p);
}

RecursiveFree 函数 - 警告：从不兼容的指针类型初始化 [-Wincompatible-pointer-types]

RecursiveFree Function - Warning: initialization from incompatible pointer type [-Wincompatible-pointer-types]

c

recursion

pointers

quadtree

nodes