dereferencing Pointer to incomplete type struct - c

Question

When I try to compile, i get an Error saying :" dereferencing Pointer to incomplete type struct Freunde"
Thats my struct:
typedef struct {
char *Name;
struct Freunde *next;
} Freunde;
The Error happens here:
while (strcmp(Anfang->next->Name, Name) != 0)
Anfang = Anfang->next;
Edit/// So here is some more Code from the Programm I do try to run:
void add(Freunde* Anfang, char* Name) {
Freunde * naechster;
while (Anfang->next != NULL) {
Anfang = Anfang->next;
}
Anfang->next = (Freunde*) malloc(sizeof(Freunde));
naechster = Anfang->next;
naechster->Name = Name;
naechster->next = NULL;
}
int main() {
Freunde *liste;
liste = (Freunde*) malloc(sizeof(Freunde));
liste->Name = "Mert";
liste->next = NULL;
add(liste, "Thomas");
add(liste, "Markus");
add(liste, "Hanko");
Ausgabe(liste);
return 0;
}

Answer 1

The main problem is that you defined the next member of your structure as struct Freunde *next; but there is no struct Freunde in your code.
First declare a struct Freunde, like this
struct Freunde
{
char *name;
struct Freunde *next;
};
and then you could typedef, but you don't have to
typedef struct Freunde Freunde;
Also:
Do not cast the return value of malloc() for these reasons
Always check that malloc() did not return NULL.

Answer 2

Another aspect of the problem, or another way to think about it, is you are creating a typedef from a struct and attempting to include a pointer to that struct type as a member.
typedef struct {
char *Name;
struct Freunde *next;
} Freunde;
As explained, when you declare the member pointer struct Freunde *next;, the compiler has no idea what Freunde is yet. Thus the error.
To remedy this, you can either do as described in the other answer, or include a struct name tag in your declaration.
typedef struct Freunde {
char *Name;
struct Freunde *next;
} Freunde;
In this case struct Freunde {... tells the compiler that there is a struct named Freunde, so when it reaches your member struct Freunde *next; it is fine.