c++ object instantiated/passed to method as reference or pointer or valueA -

i#ve looked @ couple of posts here on still dont quite it. here's little bit of code (note: wasnt trying implement linked list):

#include <iostream>  class node {      int data;  public:     node(void);     node(int data);      void setdata(int data);     int getdata(void);  };  class list {      node thenode;     node* thenode2 = null;  public:     list(node& param, node* param2);      void addnode(node& param);      void addnode2(node* param);      node* getnode(void);      node& getnode2(void);  };  node::node(void) {     this->setdata(20); };  node::node(int data) {     this->setdata(data); };  void node::setdata(int data) {     this->data = data; };  int node::getdata(void) {     return data; };  node* list::getnode(void) {     return thenode2; };  node& list::getnode2(void) {     return thenode; };  list::list(node& param, node* param2) {     thenode = param;     if (param2 != null)     {         thenode2 = param2;     }      std::cout << "thenode data " << thenode.getdata() << " " << std::endl;     std::cout << "thenode2 data " << thenode2->getdata() << " " << std::endl; };  void list::addnode(node& param) {     thenode = param;     std::cout << " thenode data " << thenode.getdata() << " " << std::endl; };  void list::addnode2(node* param) {     if (param != null)     {         thenode2 = param;     }     std::cout << "thenode2 data " << thenode2->getdata() << " " << std::endl; };    int main (void) {      node firstnode;     node secondnode(300);     node* thirdnode = new node();     // node* forthnode = new node(392);      node fifthnode(2001);      list firstlist(firstnode, thirdnode);      list secondlist(secondnode, &fifthnode);      node* asu = firstlist.getnode();      std::cout << asu->getdata() << std::endl;      delete thirdnode;     delete asu;      node somenode = firstlist.getnode2();      std::cout << somenode.getdata() << std::endl;      return 0; }; 

i references aliases. understand primitive types. still dont quite what's big difference between references , pointers when comes object instantiation, other than: - pointers can null - in case of pointers, need call delete @ point

i saw singleton implementation returns pointer object. guess way in case because need teh returned obejct on heap.

but in example? compiles, need use references , need use pointers? difference between returning reference , object , returning pointer object?

for linked lists in c++: use references next , previous nodes?

and in post can return value, in java:

when return pointer, scalar , reference in c++?

so add this:

node list::getnode3(void) {     return thenode; } 

and call this:

node someothernode = firstlist.getnode3();  std::cout << someothernode.getdata() << std::endl; 

which return value, right?

thanks takes couple of minutes provie clarity!