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

void edit_my_pointer1(int *p){
    p=NULL;
}
void edit_my_pointer2(int **p){
    *p=NULL;
}

void main(){
int x = 10;
int * p = &x;
printf("%p\n",p);  //Passing the pointer, not his address
edit_my_pointer1(p);
printf("%p\n",p);
edit_my_pointer2(&p);  //Passing the address of the pointer
printf("%p\n",p);
}