Linken list in Visual Studio 2010 problems

Question

#include <stdio.h>
#include <stdlib.h>

typedef struct node {
  int value;
  struct node *next;
}LLIST;



LLIST *list_add(LLIST **p, int i)
{
    if (p == NULL)
        return NULL;
    LLIST *first = malloc(sizeof(LLIST));
    if (first == NULL)
        return NULL;
    first->value = *first;
    *p = first;
    first->value = i;
}


int main (int argc, char** argv) {
  int i=0;

 LLIST *first = NULL;
 list_add(&first, 0);


  return (EXIT_SUCCESS);
}

Giving me errors like

IntelliSense: a value of type "void *" cannot be used to initialize an entity of type "LLIST *"

at the malloc line in list_add can you help me ??? when i am typing the code no errors are showing up intellisense is helping me to build the node code... but when compile this coming this ... can you help me how to fix it ?

Answer 1

You need to cast the result from malloc:

LLIST *first = (LLIST*)malloc(sizeof(LLIST));

edit:

You need to declare "first" before anything else:

LLIST *list_add(LLIST **p, int i)
{
    LLIST* first;
    if (p == NULL)
        return NULL;
    first = malloc(sizeof(LLIST));
    if (first == NULL)
        return NULL;
   // first->value = *first;
    *p = first;
    first->value = i;
    return first;
}

Answer 2

Are you compiling this as C code? In C++ there is no conversion from a void * to other pointer types. Check that your file has a .c extension.

Also, you have an error here:

first->value = *first;

Conceivably, either you or the compiler are getting confused by this.

Answer 3

Of course it will throw error. As Neil answered C++ there is no conversion from a void* to other pointer types.

If you want to do it in C++ use the following:

LLIST *list_add(LLIST **p, int i)
{
    if (p == NULL)
        return NULL;
    LLIST *first = (LLIST*)malloc(sizeof(LLIST));
    if (first == NULL)
        return NULL;
    //first->value = *first;
    *p = first;
    first->value = i;
}

And please reconsider the assignment

first->value = *first;

in your code