C语言模拟C++类

#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);/******** * 定义 * ********/void init(struct class *this){    this->value = 0;    this->p_next = NULL;}void destroy(struct class *this){    // TODO 释放内部成员}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;}