C++ after declaring header file my struct is not recognized

Question

I had this code in a simple file yesterday and it worked perfectly. But now I need to separate the header and the source file. And I did but code gives an error and I don't know why.

This is my header

#ifndef LISTE_HPP
#define LISTE_HPP

#include <malloc.h>
#include <stdio.h>

class Liste {
public:
  struct node {
    int veri;
    struct node *sonraki;
    struct node *onceki;
  };

  struct node *baslangic = NULL;
  int maxobeb = 0;

  struct node *dugumOlustur(int);
  void yazdir();
  void ListeyeEkle(int);
  int ModAl(int, int);
  int ObebHesapla(int, int);
};
#endif

and this is the source file

#include "Liste.hpp"


 node* Liste::dugumOlustur(int veri) //here gives error code doestn recognize node please help me 
{
    struct node* yeniDugum = (struct node*)malloc(sizeof(struct node));
    yeniDugum->veri = veri;
    yeniDugum->sonraki = NULL;
    yeniDugum->onceki = NULL;

    return yeniDugum;
}

My source file includes other fuctions too but the error is caused in that line so I didn't included all the source.

Answer 1

There are a couple of things that you could fix and improve in your code:

class Liste {
public:
  // Have a consistent naming scheme.
  // If Liste is capitalized, why isn't Node?
  struct Node {
    int veri;
    // You don't have to write struct Node, just Node is enough.
    Node *sonraki;
    Node *onceki;
  };

  // Don't use NULL, use nullptr in C++
  Node *baslangic = nullptr;
  int maxobeb = 0;

  Node *dugumOlustur(int);
  void yazdir();
  void ListeyeEkle(int);
  int ModAl(int, int);
  int ObebHesapla(int, int);
};

// It should be Liste::Node, not just node
Liste::Node* Liste::dugumOlustur(int veri)
{
    // Don't use malloc, use new.
    // Remember to delete using the delete keyword, not free().
    // Also you can use aggregate initialization to turn this into a single line.
    return new Node{veri, nullptr, nullptr};
}

Besides all that, I would strongly advise against managing memory manually if you can. Use std::unique_ptr if possible. Then you don't need to manually delete any memory.