title: Give struct as parameter to a function doesnt work
body: <p>I created a double linked list structure, and I want to use function duplaLista to connect nodes and insert values.I have actually found in someone elses question how to give struct as a parameter in function call. But it wont work for me(Incomplete type is not allowed). I also have read answers on that issue but I cant understand what am I doing wrong because I just saw it should be done that way not that I understood it completely? Can someone tell me what is wrong, and explain me why?</p>
  
  <pre><code>#include "DoubleList.h"
  #include&lt;iostream&gt;
  #include&lt;stdio.h&gt;
  #include"string"
  using namespace std;
  
  struct Cvor
  {
      Cvor *head;
      Cvor *tail;
      char vred;
  
      Cvor(const char &amp;value, Cvor *prev = NULL, Cvor *next = NULL) : vred(value),
                                                                      head(next), tail(prev)
      {}
  
  };
  
  void duplaLista(Cvor *cvor)
  {
  
  }
  
  
  int main(int argc, char *argv[])
  {   
      Cvor cvor;
  
      duplaLista(cvor);
  
      return 0;
  }
  </code></pre>