C++ example of passing arguments as references

main.cpp

#include <iostream>

using namespace std;

struct Container {
  int value;

  explicit Container(const int i) : value(i) {
    cout << "\nCreated Container per typical c-tor.\n";
  }
  Container(const Container& another) : value(another.value) {
    cout << "\nCreated Container per copy c-tor.\n";
  }
};

void testObj(Container obj) {
  cout << __FUNCTION__ << "\n\tpointer: " << &obj
       << "\n\tvalue: " << obj.value << endl;
}

void testPointer(const Container *p) {
  cout << __FUNCTION__ << "\n\tpointer: " << p
       << "\n\tvalue: " << p->value << endl;
}

void testReference(const Container &r) {
  cout << __FUNCTION__ << "\n\tpointer: " << &r
       << "\n\tvalue: " << r.value << endl;
}

int main()
{
  Container container(42);

  cout << "- - -\n";
  cout << "Original\n\tpointer: " << &container
       << "\n\tvalue: " << container.value << endl;
  cout << "- - -\n";

  testObj(container);
  testPointer(&container);
  testReference(container);

  return 0;
}