int a = 5;
int* ptr = &a;

int a2 = *ptr; // 5

int* ptr = &a;

int a = 5;   // just-a-value
int* ptr = &a;    // value a's address
int** ptr2 = &ptr; // ptr pointer's address

void a(int* ptr) {
    *ptr = 10;  //dereference, modify value
}

int r = 1;
a(&r);

void a(int** ptr) {
    *ptr = new int(20);  //deference, modify pointer
}

int* r = NULL;
a(&r);

void a(int*& ptr) {
    ptr = new int(20);  //modify pointer without dereference it
}

int* r = NULL;
a(r);

Node* n = new Node;

Node* n = malloc(sizeof(Node));

Node n;

Node n = {a,b,c...};

struct Node {
  int value;
  Node* next;
  
  Node(int v): value(v) { // assign v to value
     //constructor
     next = NULL;
  }  
}