Return from incompatible pointer type

This is a discussion on Return from incompatible pointer type within the C Programming forums, part of the General Programming Boards category; I have a struct: Code: typedef int DATA; typedef struct node { struct node *next; DATA digit; } NODE; typedef ...

  1. #1
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    Return from incompatible pointer type

    I have a struct:

    Code:
    typedef int DATA;
    typedef struct node {
    struct node *next;
    DATA digit; 
    } NODE;
    
    typedef struct {
    struct node *head; 
    int size; // number of elements in the list 
    } LIST_HEAD;

    I write reverseList fuction to reverses the order of the elements in the list, return a pointer to head of the reversed list.
    Everything seem works fine, but I get the [Warning] return from incompatible pointer type at the return line. Please help to indicate my problem in this code. Thank you.


    Code:
    LIST_HEAD *reverseList(LIST_HEAD *list)	
       NODE  *p,*q,*r;
    	p=list->head;
    	q=NULL;
    
    	while(p!=NULL)
    	{
    	    r=q;
    	    q=p;
    	    p=p->next;
    	    q->next=r;
    	}
    	p = q;
    	list->head=p;
    	return p; //error here
    }
    Last edited by aladin; 03-22-2009 at 08:51 AM.

  2. #2
    30 Helens Agree neandrake's Avatar
    Join Date
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    You are returning *p, a pointer to a NODE. The way your function is declared, it wants to return a pointer to a LIST_HEAD. Typically your head node is not a different struct than regular nodes, and will contain data.
    Environment: OS X, GCC / G++
    Codes: Java, C#, C/C++
    AOL IM: neandrake, Email: neandrake (at) gmail (dot) com

  3. #3
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    Thanks for quick reply. So I realize that I should return list . I'll try it.

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