Segmentation fault on program with scanf

Question

This is a small piece of code that I made while trying to understand how malloc and pointers work.

#include <stdio.h>
#include <stdlib.h>

int *buffer (int count)
{
  int *buffer = malloc (count * sizeof(int));

  for (int i = 0; 0 <= i && i < count; i++)
    {
      buffer[i] = 0;
    }

  return &buffer;
}

int main ()
{
  int size = 0;
  int i = 0;
  scanf ("%d", &size);

  int *num = buffer (size);
  while (i < size)
    {
      scanf ("%d", &num[i]);
      i++;
    }
}

For some reason that I can't understand, I keep getting a segmentation fault. This error repeatedly happens on the last scanf() and I do not know why. I know i have to pass pointer to scan f and num is already a pointer so i thought that i would not need to include the &. But, I received a segmentation fault earlier if i do not. Also, I believe I have allocated the correct amount of space using malloc but I am not sure. Any help with what is happening here would be appreciated.

Answer 1

You returned the pointer to the local variable buffer, which will banish on exiting the function buffer.

You should remove the & used in the return statement and return the pointer to allocated buffer.

Also checking whether malloc() is successful should be added.