oop_in_c/Square.c

#include <stdlib.h>
#include <stdio.h>

#include "Square.h"

void Square_constructor (Square *this, double a)
{
  printf ("Square_constructor (%lu, %f) called\n",
          (unsigned long) this,
          a);
  this->a = a;
}

void Square_destructor (Square *this)
{
  printf ("Square_destructor (%lu) called\n",
          (unsigned long) this);
}

void Square_copy (Square *dest, const Square *src)
{
  printf ("Square_copy (%lu, %lu) called\n",
          (unsigned long) dest,
          (unsigned long) src);
  dest->a = src->a;
}

Square* Square_clone (const Square *this)
{
  Square *square = Square_new (0.0);
  printf ("Square_clone (%lu) called\n",
          (unsigned long) this);
  Square_copy (square, this);
  printf ("Square_clone (%lu) returns %lu\n",
          (unsigned long) this,
          (unsigned long) square);

  return square;
}

void Square_destroy (Square *this)
{
  printf ("Square_destroy (%lu) called\n",
          (unsigned long) this);
  free (this);
}

const char* Square_type (const Square *this)
{
  static const char *square_type_str = "Square";
  printf ("Square_type (%lu) called\n",
          (unsigned long) this);
  printf ("Square_type (%lu) returns \"%s\"\n",
          (unsigned long) this,
          square_type_str);

  return square_type_str;
}

void Square_draw (const Square *this)
{
  printf ("Square_draw (%lu) called\n",
          (unsigned long) this);
  printf ("Drawing Square with %f side\n",
          this->a);
}

double Square_area (const Square *this)
{
  double area = this->a * this->a;
  printf ("Square_area (%lu) called\n",
          (unsigned long) this);
  printf ("Square_area (%lu) returns %f\n",
          (unsigned long) this,
          area);

  return area;
}

void Square_resize (Square *this, double a)
{
  printf ("Square_resize (%lu, %f) called\n",
          (unsigned long) this,
          a);
  this->a = a;
}

double Square_diag_length (const Square *this)
{
  double diag_length = ((Square *)this)->a * 1.41421356;

  printf ("Square_diag_length (%lu) called\n",
          (unsigned long) this);
  printf ("Square_diag_length (%lu) returns %f\n",
          (unsigned long) this,
          diag_length);

  return diag_length;
}

/* public */
Square* Square_new (double a)
{
  static Square_interface vtable =
    {
      {
        {
          (void* (*) (const void *)) Square_clone,
          (void (*) (void *)) Square_destroy
        },
        (const char* (*) (const Figure *)) Square_type,
        (void (*) (const Figure *)) Square_draw,
        (double (*) (const Figure *)) Square_area
      },
      Square_resize,
      Square_diag_length
    };
  Square *square = malloc (sizeof (*square));

  Square_constructor (square, a);

  printf ("Square_new (%f) returns %lu\n",
          a,
          (unsigned long) square); 

  square->vtable = &vtable;

/*goto end;
err:

end:*/

  return square;
}