Wrinting an array to a file in C

#include <stdio.h>
#include <stdlib.h>
#define f  fflush(stdin)
int main(){
   int n,i;
   scanf("%d", &n);
   int arr[n],aa[n];
   for(i = 0 ; i < n; ++i)
    scanf("%d", &arr[i]);
    f;
   FILE *fp = fopen("file.txt", "w");

   fwrite(arr, sizeof(arr), 1, fp);
   fclose(fp);
  FILE *p= fopen("file.txt", "r");
  fread(aa, sizeof(aa), 1, p);
  fclose(p);
  for(i = 0; i < n; i++)printf("%d ", aa[i]);
  return 0;
  return 0;
}