c - 在 C 中初始化嵌套结构的正确方法

Question

当使用嵌套结构时，我倾向于做如下的事情。我想知道在这种特殊情况下这是否是初始化 structs 的正确方法，或者是否有更好的方法。

#include <string.h>
#include <stdlib.h>

typedef struct inner_struct { 
   char *name;
   int account;
} inner;

typedef struct outer_struct {
   int count;
   char *company; 
   inner *my_inner;
} outer;

outer *
initialize_outer (size_t max) {
   outer *out = malloc(sizeof (outer) * max);
   if (out) {
      memset(out, 0, sizeof *out * max);
      out->count = 0;
      out->company = NULL; 
   }   
   return out;
}

inner *
initialize_inner () {
   inner *in = malloc(sizeof (inner));
   if (in) {
      memset(in, 0, sizeof *in);
      in->account = 0;
      in->name = NULL; 
   }   
   return in; 
}

int main(int argc, char *argv[]){
   int i;
   size_t max_out = 20;
   outer *my_out = initialize_outer(max_out);
   for (i = 0; i<max_out;i++) {
      my_out[i].my_inner = initialize_inner();
   }
}

Answer 1

为什么不使用calloc():

outer *
initialize_outer (size_t max) {
    return calloc(max, sizeof(outer));
}

inner *
initialize_inner (size_t max) {
    return calloc(max, sizeof(inner));
}

---

但是，为了简单起见，我可能会这样做:

typedef struct outer_struct {
    int count;
    char *company; 
    inner my_inner[];
} outer;

outer *
initialize (size_t max_out, size_t max_in) {
    return calloc(1, (sizeof (outer) + sizeof (inner) * max_in) * max_out);
}

int main(int argc, char *argv[]){
    size_t max_out = 20, max_in = 10; 
    outer *my_out = initialize(max_out, max_in);
    ...
}