// set all values in the hash table to null
for(int i = 0; i < HASH_SIZE; i++)
{
hashtable[i] = NULL;
}
I keep getting this error message in response to hashtable[i]:
assignment makes integer from pointer without a cast [-Werror]
Why?
Add a comment
|
2 Answers
If hashtable is an array of integers then hashtable[i] expects an integer and NULL is a pointer.
So you're trying to assign a pointer value to an integer variable(without a cast), this is usually just a warning but since you have -Werror all warnings turn into errors.
Just use 0 instead of NULL.
1 Comment
hannah
Ah, I see. I could also declare an array of pointers and store the value that way. I get it now. Thanks!
NULL is defined as (void*)0 in stddef.h
#ifndef _LINUX_STDDEF_H
#define _LINUX_STDDEF_H
#undef NULL
#if defined(__cplusplus)
#define NULL 0
#else
#define NULL ((void *)0)
#endif
#endif
If the hashtable is integer array, like
#include <stdio.h>
#define HASH_SIZE 100
int main()
{
int i = 0, hashtable[HASH_SIZE];
for(i = 0; i < HASH_SIZE; i++)
{
hashtable[i] = NULL;
}
return 0;
}
this warning: assignment makes integer from pointer without a cast will be shown.
2 Comments
Jens
What makes you believe the OP uses Linux? What makes you believe NULL must be defined in this particular way? Note that making assumptions by extrapolation from one system makes you in for surprises. Instead, reading and citing the ISO C Standard is likely to provide definitive answers. Such answers are independent of OS and header contents.
Jeyaram
@Jens, Thanks. I will try to follow ISO C std :)