/*
 * Program to illustrate that class instaces in C++ can be created on the
 * stack (without new), unlike Java. Passing class instances to functions,
 * and during assignment statements create "a copy" of the actual/RHS
 * variable instance.
 */
#include <iostream>

using namespace std;

// CHANGE1: Change dynamic allocation of class variable to static
// allocation. All fields in the structure are not passed "by value".
// Any change made in "frap" will not be reflected in "main".
#define CHANGE1 0

// CHANGE2: Passing the class variable "by reference". Any changes made in
// "frap" are now visible in "main" (similar to Java behavior).
#define CHANGE2 0

class Blip{
public:
  int local;
#if CHANGE1 // Change1: to "int ptr[2]", and see what happens.
  int ptr[2];
#else  
  int *ptr;
#endif  
};


#if CHANGE2 // Change2: to "void frap(Blip &arg)"
void frap(Blip &arg)
#else  
void frap(Blip arg)
#endif  
{
  cout << "Frap: START function: local: " << arg.local
       << " ptr[0]: " << arg.ptr[0]
       << " ptr[1]: " << arg.ptr[1] << endl << endl;
  
  arg.local = 200;
  arg.ptr[0] = 10;
  arg.ptr[1] = 20;

  cout << "Frap: END function: local: " << arg.local
       << " ptr[0]: " << arg.ptr[0]
       << " ptr[1]: " << arg.ptr[1] << endl << endl;  
}


int main()
{
  Blip main_b;
  
  main_b.local = 100;
#if !CHANGE1  // Change1: Comment out this line.
  main_b.ptr = new int[2]; 
#endif  
  main_b.ptr[0] = 1;
  main_b.ptr[1] = 2;
  cout << "Main: Values BEFORE function call: local: " << main_b.local
       << " ptr[0]: " << main_b.ptr[0]
       << " ptr[1]: " << main_b.ptr[1] << endl << endl;

  frap(main_b);

  cout << "Main: Values AFTER function call: local: " << main_b.local
       << " ptr[0]: " << main_b.ptr[0]
       << " ptr[1]: " << main_b.ptr[1] << endl << endl;

  return 0;
}