implicit declaration

Hey guys i have a problem im trying to make a program that inserts a node but when im calling the function in my main i get an implicit declaration error.

Any suggestions?

Code:

---

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

typedef struct ListNode * ListNodePtr;

typedef struct ListNode
{
  int data;
  ListNodePtr * next;


}ListNode;

int main (void)
{
  int data;
  ListNodePtr root = NULL;


  if(!ListInsert(root, data))
  {
    printf("Insertion of node falied\n");
  }


  return 0;
}

int ListInsert(ListNodePtr *head, int data)
{


  return 0;
}

---

Either define the function before you call it, or prototype it first.

Code:

---

void foo( void ); /* prorotype it */

int main( void )
{
    foo( ); /* call it */
    return 0;
}

/* define it */
void foo( void )
{
    ...whatever...
}

---

Quzah.

Here ya go. One problem was you didn't prototype your function. Another was your if statement.

Code:

---

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

typedef struct ListNode * ListNodePtr;
typedef struct ListNode
{
  int data;
  ListNodePtr * next;
}ListNode;

int ListInsert(ListNodePtr *head, int data);

int main (void)
{
  int data;
  ListNodePtr root = NULL;


  if(!ListInsert(&root, data))
  {
    printf("Insertion of node falied\n");
  }


  return 0;
}

int ListInsert(ListNodePtr *head, int data)
{
  return 0;
}

---

Edit: Argh... beaten to the punch.

I thought it would b the prototype but wat do i pass to the parameters in the prototype of the function

You pass nothing, infact you don't even have to declare variables to the parameters.

You can prototype like this:

Code:

---

void function(float, float, char, float&, float&);

---

ahhh kewl thanks for that got... i thought you still had to pass variables when prototyping

Quote:

---

Originally Posted by SlyMaelstrom

You pass nothing, infact you don't even have to declare variables to the parameters.

You can prototype like this:

Code:

---

void function(float, float, char, float&, float&);

---

---

Except this prototype is C++ and not C. ;)


Quzah.

Ooops, sorry, I forgot this was the C programming board.

Quote:

---

Originally Posted by SlyMaelstrom

You pass nothing, infact you don't even have to declare variables to the parameters.

You can prototype like this:

Code:

---

void function(float, float, char, float&, float&);

---

---

That's legal C++, not legal C. Perhaps you meant

Code:

---

void function(float, float, char, float *, float *);

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