Why is my pointer not null after free?

Question

void getFree(void *ptr)
{
    if(ptr != NULL)
    {
        free(ptr);
        ptr = NULL;
    }
    return;
}
int main()
{
char *a;
a=malloc(10);
getFree(a);
if(a==         


        

Answer 1

Because the getFree() function takes a copy of the pointer. ptr and c are both pointers, but they are different variables. It's the same reason why this function will output "6":

void Magic(int x)
{
    x = 1;
}

void main()
{
    int a = 6;
    Magic(a);
    printf("%d", a);
}