Array initialization giving error: initializer element is not constant

Asked May 28 '16 at 07:06

Active May 28 '16 at 08:36

Viewed 22 times

I am having trouble with following fragment of my code giving error:

solution.c:1:1: error: initializer element is not constant
 int *arr=malloc(sizeof(int)*100000);
 ^
solution.c:2:1: error: initializer element is not constant
 int *min=malloc(sizeof(int)*100000);

Here is my code fragment:

int *arr=malloc(sizeof(int)*100000);
int *min=malloc(sizeof(int)*100000);
int top1;

void init() {
    memset(arr,-1,sizeof(arr));
    memset(min,-1,sizeof(min));
    top1=-1;
}

what's going wrong?

NOTE: This init() function would be called for every test case, so I am clearing memory and arr, min, top1 are global

edited May 28 '16 at 08:36

piyushj

1,546
5
21
29

asked May 28 '16 at 07:06

Naveen Kumar

Nitpick: `memset(arr,-1,sizeof(arr));` will set only `4` bytes to `-1`. – haccks May 28 '16 at 07:10
but error is popping up at initial 2 lines itself? – Naveen Kumar May 28 '16 at 07:13
@kaylum: I checked that, but couldn't help – Naveen Kumar May 28 '16 at 07:14
1

Why not? Both the linked question and even the error message itself tells you the exact problem. Initializers for variables with static duration must be constant expression - ie, known at compile time. A `malloc` call is not a constant expression. – kaylum May 28 '16 at 07:15
so what should be the fix, can you plz elaborate? – Naveen Kumar May 28 '16 at 07:17
1

Change to `int arr[100000];`. Or leave as `int *arr;` and then have `init` do the `malloc`. – kaylum May 28 '16 at 07:17
Also `sizeof(arr)` does not work because `arr` is not actually a C array. `sizeof(arr)` will only give you `sizeof(int *)` which is always going to be 4 or 8. – kaylum May 28 '16 at 07:21
Yeah, thanks a lot. It helped!! – Naveen Kumar May 28 '16 at 07:23

Array initialization giving error: initializer element is not constant

0 Answers0