c++ - working with parameter from the constructor -

i have following problem: whats best way work on object got parameter constructor? don't want work copy because, initial object won't change.

obj obj;  myclass::myclass(obj& obj) {   this->obj = obj; //copy }  void myclass::dosometh() {  obj.add(....); //working copy } 

my solution use pointer:

obj* obj;  void myclass::myclass(obj& obj) {   this->obj = &obj;  }  void myclass::dosometh() {  obj->add(....);  } 

or

    obj* obj;     myclass::myclass(obj* obj)     {       this->obj = obj;      }      void myclass::dosometh()     {      obj->add(....);      } 

what thing solution? or there better solutions?

there nothing wrong using pointer member-variable avoid making copy. need confident object being pointed to, obj, outlive myclass contains pointer.

also, recommend using constructor initializer list initialize pointer directly:

class myclass {  private:   obj* obj_;  public:   myclass(obj* obj) : obj_(obj) { } }; 

in similar way have reference member-variable restricts can class. e.g not assignable:

class myclass {  private:   obj& obj_;  public:   myclass(obj& obj) : obj_(obj) { } }; 

if not confident of lifetime of object being pointed consider std::weak_ptr or std::shared_ptr:

#include <memory>  struct obj { };  class myclass {  private:   std::weak_ptr<obj> obj_;  public:   myclass(std::weak_ptr<obj> obj) : obj_(std::move(obj)) { }   void dosomething() {     std::shared_ptr<obj> obj = obj_.lock();     if (obj) {       // obj...     }      } };  int main() {   std::shared_ptr<obj> obj = std::make_shared<obj>();   myclass mc(obj); }