C 結構 memory 分配

Question

這里是樹數據結構的相關header：

#include <stdlib.h>
#ifndef KDTREE_H
#define KDTREE_H
#define DEFAULT_NUMBER_OF_DIMENSIONS 1
#define KD_TREE_HEAP_SIZE 100
#define MAX_DIMENSIONS 32
//References: https://www.geeksforgeeks.org/k-dimensional-tree/
//References:  https://www.cs.cmu.edu/~ckingsf/bioinfo-lectures/kdtrees.pdf
//References:https://iq.opengenus.org/k-dimensional-tree/

  /*
     * Representation of a kd tree
     */
    typedef struct tree_
    {
        struct tree *left; 
        struct tree *right; 

        float * info =  (float *) calloc (MAX_DIMENSIONS, sizeof(float));
        float distance_to_neighbor;
    } tree;

float * info = (float *) calloc (MAX_DIMENSIONS, sizeof(float)); 拋出編譯器錯誤：

kdtree.h:31:22: error: expected ':', ',', ';', '}' or '__attribute__' before '=' token
         float * info =  (float *) calloc (MAX_DIMENSIONS, sizeof(float));

我能夠在結構之外而不是在結構內部進行動態分配嗎？ 如何在結構內部進行預分配。

Answer 1

這可能有效，但是沒有calloc()或其他任何東西：

typedef struct tree_
{
    struct tree *left; 
    struct tree *right; 

    float info[MAX_DIMENSIONS];
    float distance_to_neighbor;
} tree;