用C結構體來實作面向對象程式設計，ti xDAIS标準算法就這麼搞的

用C結構體來實作面向對象程式設計，ti xDAIS标準算法就這麼搞的。

測試代碼如下：

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


typedef struct Alg_Obj{
	struct Alg_Fxn* fxns;
}Alg_Obj;

typedef Alg_Obj *Alg_Handle;

typedef struct Alg_Fxn{
	void (*process)(Alg_Handle handle);
	void (*control)(Alg_Handle handle);
}Alg_Fxn;

void Alg_process(Alg_Handle handle)
{
	handle->fxns->process(handle);
	printf("in Alg_process.. \n");
}

void Alg_control(Alg_Handle handle)
{
	handle->fxns->control(handle);
	printf("in Alg_control.. \n");
}


struct triangle{
	Alg_Handle handle;
	int a;
	int b;
	int c;
};
void tri_process(Alg_Handle handle)
{
	struct triangle *t = (struct triangle*)handle; 
	int a = t->a;
	int b = t->b;
	int c = t->c;
	printf("  [in tri_process] sum=%d\n",a+b+c);
}
void tri_control(Alg_Handle handle)
{
	struct triangle *t = (struct triangle*)handle; 
	int a = t->a;
	int b = t->b;
	int c = t->c;
	printf("  [in tri_control] sum=%d\n",(a+b+c)*2);
}

Alg_Fxn gfxns = {
	tri_process,
	tri_control,	
};


int main()
{
	struct triangle *ret = (struct triangle*)malloc(sizeof(struct triangle));
	ret->handle->fxns=&gfxns;
	ret->a = 2;
	ret->b = 3;
	ret->c = 4;
	
	Alg_Handle Handle= (Alg_Handle)ret;
	//第一種調用，注意結果
	gfxns.process(Handle);
	gfxns.control(Handle);

	printf("\n**********************************\n");
	
	//第二種調用，注意結果
	Alg_process(Handle);
	Alg_control(Handle);

	free(Handle);
	return 0;
	
}
/*
[[email protected] TestCode]# ./a.out 
  [in tri_process] sum=9
  [in tri_control] sum=18

**********************************
  [in tri_process] sum=9
in Alg_process.. 
  [in tri_control] sum=18
in Alg_control.. 

*/