闲来没事，看了看sqlite的源码，突然想用c实现c++，写了如下demo，自我感觉不错

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

struct Class;
typedef struct Class _Class;

struct IMethod
{
	void (*ctor)(_Class *c);
	void (*dtor)(_Class *c);
	int (*sum)(_Class* c);
	int (*getValueA)(_Class* c);
	int (*getValueB)(_Class* c);
	void (*setValueA)(_Class*c, int a);
	void (*setValueB)(_Class *c, int b);
};
typedef struct IMethod _IMethod;

typedef struct Class
{
	//数据
	int m_a;
	int m_b;

	//接口
	_IMethod m_method;
} _Class;

int _sum(_Class *c)
{
	return c->m_a+c->m_b;
}

int _getValueA(_Class *c)
{
	return c->m_a;
}

int _getValueB(_Class *c)
{
	return c->m_b;
}

void _setValueA(_Class *c, int a)
{
	c->m_a = a;
}

void _setValueB(_Class *c, int b)
{
	c->m_b = b;
}

void _ctor(_Class *c)
{
	printf("create new _Class\n");

	//初始化数据，构造函数
	c->m_method.sum = &_sum;
	c->m_method.getValueA = &_getValueA;
	c->m_method.getValueB = &_getValueB;
	c->m_method.setValueA = &_setValueA;
	c->m_method.setValueB = &_setValueB;

	c->m_a = 0;
	c->m_b = 0;
}

void _dtor(_Class *c)
{
	printf("delete _Class\n");

	//析构函数
}

//_Class的对象工厂
_Class *newClass()
{
	_Class* obj= (_Class*)malloc(sizeof(_Class));
	_ctor(obj);
	return obj;
}

void deleteClass(_Class * c)
{
	_dtor(c);
	free(c);
}

#define CXX_CALLER(obj, fun,...)	obj->m_method.fun(obj, __VA_ARGS__);

int main(int argc, char *argv[])
{
	_Class *c = newClass();

	int a=0, b=0, sum=0;
	CXX_CALLER(c, setValueA, 100);
	CXX_CALLER(c, setValueB, 200);
// 	c->m_method.setValueA(100);
// 	c->m_method.setValueB(200);

// 	a = c->m_method.getValueA(c);
// 	b = c->m_method.getValueB(c);
// 	sum = c->m_method.sum(c);
	a = CXX_CALLER(c, getValueA);
	b = CXX_CALLER(c, getValueB);
	sum = CXX_CALLER(c, sum);

	printf("a=%d, b=%d, sum=%d\n", a, b, sum);

	deleteClass(c);

	getchar();
	return 0;
}