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

struct class
{
    int value;
    struct class *p_next;

    void (*init)   (struct class *this);
    void (*destroy)(struct class *this);

    void (*set_value)(struct class *this, int value);
    int  (*get_value)(struct
 
 class *this);
};
struct class * create_instance();
void destroy_instance(struct class *p_instance);

/********
 * 定義 *
 ********/
void init(struct class *this)
{
    this->value = 0;
    this->p_next = NULL;
}
void destroy(struct class *this)
{
    // TODO 釋放內部成員
}
void set_value(struct class *this
 
, int value)
{
    this->value = value;
}
int get_value(struct class *this)
{
    return this->value;
}
struct class * create_instance()
{
    struct class *p_instance = (struct class *)malloc(sizeof(struct class));
    memset(p_instance, 0, sizeof(struct class));

    p_instance->init      = init;
    p_instance->destroy   = destroy;
    p_instance->set_value = set_value;
    p_instance->get_value = get_value;

    p_instance->init(p_instance);
    return
 
 p_instance;
}
void destroy_instance(struct class *p_instance)
{
    p_instance->destroy(p_instance);
    free(p_instance);
}

int main()
{
    struct class *p_instance = create_instance();

    //p_instance->set_value(p_instance, 5);
    printf("%d\n", p_instance->get_value(p_instance));

    destroy_instance(p_instance);
    return 0;
}