gistfile1.cpp

#include <stdio.h>
#include <math.h>
#include <stddef.h>

class Square
{
private:
  float _edge;

public:
  float edge_getter() {
      return _edge;
    }
void edge_setter(float value) {
      _edge = value;
    }
class property_edge
{
int padding;
public:
operator float () { return ((Square*)((char*)this - offsetof(Square, edge)))->edge_getter(); }
float & operator = (float value) { ((Square*)((char*)this - offsetof(Square, edge)))->edge_setter(value); }} edge;
  
  float area_getter() {
      return _edge * _edge;
    }
void area_setter(float value) {
      _edge = sqrtf(value);
    }
class property_area
{
int padding;
public:
operator float () { return ((Square*)((char*)this - offsetof(Square, area)))->area_getter(); }
float & operator = (float value) { ((Square*)((char*)this - offsetof(Square, area)))->area_setter(value); }} area;
};

void print(float edge, float area)
{
  printf("edge = %f, area = %f\n", edge, area);
}

int main()
{
  Square s;
  s.area = 25;
  print(s.edge, s.area);
  s.edge = 3;
  print(s.edge, s.area);
  return 0;
}