CODEWITHSUNDEEP
clistlinked-list
GraphicalDot
GraphicalDot

Reputation: 2821

Linked list syntax

typedef struct  {
 char name [25] ;
 char breed [25] ;
 int age  ; 
 struct animal *next ;
 } animal ;

 animal *ptr1 , *ptr2 , *prior ;
 ptr1 = (animal*)malloc( sizeof (animal) ) ;
 strcpy ( (*ptr1).name , "General" ) ;
 strcpy ( (*ptr1).breed , "Foreign breed" ) ;
 (*ptr1).age = 8 ;


 (*ptr1).next = NULL ;
 prior =ptr1 ;
 printf ("%s\n" , (*prior).name ) ;
 printf ("%s\n" , (*prior).breed ) ;
 printf ("%d\n" , (*prior).age ) ;
 printf ("%p\n" , (*prior).next ) ;
 free (ptr1) ;
 ptr1 = (animal*)malloc( sizeof (animal) ) ;
 strcpy ( (*ptr1).name , "General 1" ) ;
 strcpy ( (*ptr1).breed , "Abroad breed" ) ;
 (*ptr1).age = 24 ;
 (*ptr1).next = NULL ;
 (*prior).next = ptr1 ;

Here is the code to draw a linked list. The whole code when executes shows an error in the last line:

In function ‘main’: warning: assignment from incompatible pointer type [enabled by default]

Upvotes: 1

Views: 1122

Answers (5)

Bogdan
Bogdan

Reputation: 51

That is actually a warning, not an error. I don't get why are you using (*s).m instead of s->m. It is simpler and more natural. I don't see function main in your code and the line where you get the error, I suppose all your code except the struct declaration is the function main. Try declaring your structure like this (you may also need to add a "typedef struct animal", depending on your compiler): struct animal { ... animal *next; };

Upvotes: 0

Jens Gustedt
Jens Gustedt

Reputation: 78903

The "tag" name space (the name after the struct) and the identifier name space (the one you declare with typedef, eg.) are distinct in C.

The easiest, I find, is to always forward declare the struct tag and the typedef in one go:

typedef struct animal animal;

From then on you could easily use the typedef name even inside the declaration of the struct:

struct animal {
  ....
  animal* next;
};

Upvotes: 0

ouah
ouah

Reputation: 145829

Change your declaration to:

typedef struct animal {
    char name [25] ;
    char breed [25] ;
    int age;
    struct animal *next;
 } animal;

The structure tag animal has been added to the declaration. You now have the type animal an alias for struct animal.

Upvotes: 1

StoryTeller - Unslander Monica
StoryTeller - Unslander Monica

Reputation: 170055

change your structue definition to this

typdef struct Animal_
{
  char name [25];
  char breed [25];
  int age; 
  struct Animal_* next;
} Animal;

Without Animal_ the struct is an anonymous struct, and cannot have a pointer to it.

Upvotes: 1

James M
James M

Reputation: 16718

animal is the name of the typedef, not the struct. Try this instead:

typedef struct _animal {
    char name [25];
    char breed [25];
    int age; 
    struct _animal *next;
} animal;

Upvotes: 0

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