How to solve the error "assignment makes integer from pointer without a cast"?

Question

Here is the piece of code: I wonder where my mistake is? I have a structure named country, working with linked lists, and here is my function for searching:

country *search(char *v)
{
   country *c; c=head;
   while(c)
   {
           if(strcmp(c->name,v)==0)
           {return c;}
           c=c->next;
           if(c==head) break;}
           return (void *)-1;}

In main I have (k is a int variable):

printf("  \n\tEnter name of country for searching:   ");
                fflush(stdin); gets(v);
                k = search(v); // Function for searching
                if(k>=0)
                {puts("\n\t Info about Country: \n ");

When I compile this in Dev C++, I get:

[Warning] assignment makes integer from pointer without a cast [enabled by default]

How do I fix this problem?

Instead of assigning the return value of `search` to a variable of type `int`, create a variable of type `country*` and assign the return value of `search` to that. — R Sahu, Mar 08 '15 at 07:02
Please learn to use a more orthodox code layout; your code fragments are almost unreadable and very hard to comprehend because the layout is extraordinary — especially the first fragment. Also, beware of [using `fflush(stdin)`](http://stackoverflow.com/questions/2979209/using-fflushstdin) and [why the `gets()` function cannot be used safely](http://stackoverflow.com/questions/1694036/why-is-the-gets-function-dangerous-why-should-it-not-be-used). — Jonathan Leffler, Mar 08 '15 at 07:10
As @RSahu said, your function `search()` is declared to return a `country *`, so assigning its result to `k`, an `int`, is bound to give the error. Return 0 or NULL for a missing value when the non-missing return type is a pointer. Returning `(void *)-1` is aconventional (though not without standardized precedent). — Jonathan Leffler, Mar 08 '15 at 07:12
What did you expect `k` to contain after running `k = search(v)`? — user253751, Mar 08 '15 at 08:04
Doesn't the error messages together with the code line it issues says it all? — alk, Mar 08 '15 at 08:41
@immibis I expected an integer, I wondered it would be ok if k would contain the length of my string... or something like that — aB61, Mar 08 '15 at 09:39
@aB61 but how can it be an integer if `search` doesn't return an integer? — user253751, Mar 08 '15 at 10:15

score 3 · Accepted Answer · answered Mar 08 '15 at 07:11

Couple of things to fix:

The return value of search when you don't find what you are searching for:

country *search(char *v)
{
   country *c; c=head;
   while(c)
   {
      if(strcmp(c->name,v)==0)
      {
         return c;
      }
      c=c->next;
      if(c==head) break;
   }

   // Don't use -1 as an invalid search.
   // Use NULL instead.
   // return (void *)-1;
   return NULL;
}

Use the right variable type to assign the return value of search.

// Don't use k, which is of type int.
// Use a variable of the right type.
// k = search(v);
country* cPtr = search(v);
if( cPtr )
{
   puts("\n\t Info about Country: \n ");
}

How to solve the error "assignment makes integer from pointer without a cast"?

1 Answers1