Реализовать в виде односвязного списка - C (СИ)

#include <stdio.h>
#include <stdlib.h>
 
#define MAX_LOCATION_LENGTH     128
#define MAX_PERSON_NAME_LENGTH  64
 
struct Voucher
{
  double price;
  char location[MAX_LOCATION_LENGTH + 1];
};
 
struct Client
{
  unsigned int id;
  char surname[MAX_PERSON_NAME_LENGTH + 1];
  char name[MAX_PERSON_NAME_LENGTH + 1];
  struct Voucher voucher;
};
 
struct OneWayList
{
  struct Client clientData;
  struct OneWayList* next;
};
 
void AddToList(struct OneWayList** const rootPtr, const struct Client client)
{
  if (*rootPtr == NULL)
  {    
    *rootPtr = malloc(sizeof(**rootPtr));
    
    (*rootPtr)->clientData = client;
    (*rootPtr)->next = NULL;
  }
  else
  {
    struct OneWayList* p = *rootPtr;  
    
    while (p->next != NULL) p = p->next;
    
    p->next = malloc(sizeof(*p));
    
    p->next->clientData = client;
    p->next->next = NULL;
  }
}
 
void PrintList(const struct OneWayList* const root)
{
  const struct OneWayList* p = root;
  
  int i = 0;
  
  printf("===== List values: =====\n");
  
  while (p != NULL)
  {
    printf("Client %3d:\n"
      "  ID: %u\n"
      "  Name: %s\n"
      "  Surname: %s\n"
      "  Voucher data:\n"
      "    location: %s\n"
      "    price: %f\n",
      ++i,
      p->clientData.id,
      p->clientData.name,
      p->clientData.surname,
      p->clientData.voucher.location,
      p->clientData.voucher.price);
      
    p = p->next;
  }
}
 
void ClearList(struct OneWayList** rootPtr)
{
  while (*rootPtr != NULL)
  {
    struct OneWayList* p = (*rootPtr)->next;
    free(*rootPtr);
    *rootPtr = p;
  }
}
 
int main(void)
{
  struct OneWayList* clientListRoot = NULL;
  
  struct Client clientIvanov = {
    .id = 119,
    .surname = "Ivanov",
    .name = "Ivan",
    .voucher.price = 12.45,
    .voucher.location = "Thailand"
  };
  
  struct Client clientPetrov = {
    .id = 187256,
    .surname = "Petrov",
    .name = "Sergey",
    .voucher.price = 9.5,
    .voucher.location = "India"
  };
  
  struct Client clientSidorov = {
    .id = 11223,
    .surname = "Sidorov",
    .name = "Oleg",
    .voucher.price = 112.99,
    .voucher.location = "Florida, USA"
  };
  
  struct Client clientSokolova = {
    .id = 998,
    .surname = "Sokolova",
    .name = "Oksana",
    .voucher.price = 229.99,
    .voucher.location = "Mallorca"
  };
  
  AddToList(&clientListRoot, clientIvanov);
  AddToList(&clientListRoot, clientPetrov);
  AddToList(&clientListRoot, clientSidorov);
  AddToList(&clientListRoot, clientSokolova);
  
  PrintList(clientListRoot);
  
  ClearList(&clientListRoot);
  
  return 0;
}