How memory can be allocated for the array in the following program?

Question

#include <stdio.h>

int main(void)
{
  int a=17;
  scanf("%d",&a);

  int arr[a];

  printf("%lu",sizeof(arr));
}

Memory for array "arr" should be allocated at compile time but in this case it takes the value of "a" from the user(run-time) and allocates the same size for the array.

Answer 1

Nice question,
Please note that allocation of memory is done at run time not compile time,
During compilation compiler will just create a table for this variable, but actual allocation is done at run time.