用C结构体来实现面向对象编程，ti xDAIS标准算法就这么搞的（1）

用C结构体来实现面向对象编程，ti xDAIS标准算法就这么搞的。

测试代码如下：

1. #include <stdio.h>
2. #include <stdlib.h>
3. #include <string.h>
4. typedef struct Alg_Obj{
5. struct Alg_Fxn* fxns;
6. }Alg_Obj;
7. typedef Alg_Obj *Alg_Handle;
8. typedef struct Alg_Fxn{
9. void (*process)(Alg_Handle handle);
10. void (*control)(Alg_Handle handle);
11. }Alg_Fxn;
12. void Alg_process(Alg_Handle handle)
13. {
14. handle->fxns->process(handle);
15. printf("in Alg_process.. \n");
16. }
17. void Alg_control(Alg_Handle handle)
18. {
19. handle->fxns->control(handle);
20. printf("in Alg_control.. \n");
21. }
22. struct triangle{
23. Alg_Handle handle;
24. int a;
25. int b;
26. int c;
27. };
28. void tri_process(Alg_Handle handle)
29. {
30. struct triangle *t = (struct triangle*)handle;
31. int a = t->a;
32. int b = t->b;
33. int c = t->c;
34. printf("  [in tri_process] sum=%d\n",a+b+c);
35. }
36. void tri_control(Alg_Handle handle)
37. {
38. struct triangle *t = (struct triangle*)handle;
39. int a = t->a;
40. int b = t->b;
41. int c = t->c;
42. printf("  [in tri_control] sum=%d\n",(a+b+c)*2);
43. }
44. Alg_Fxn gfxns = {
45. tri_process,
46. tri_control,
47. };
48. int main()
49. {
50. struct triangle *ret = (struct triangle*)malloc(sizeof(struct triangle));
51. ret->handle->fxns=&gfxns;
52. ret->a = 2;
53. ret->b = 3;
54. ret->c = 4;
55. Alg_Handle Handle= (Alg_Handle)ret;
56. //第一种调用，注意结果
57. gfxns.process(Handle);
58. gfxns.control(Handle);
59. printf("\n**********************************\n");
60. //第二种调用，注意结果
61. Alg_process(Handle);
62. Alg_control(Handle);
63. free(Handle);
64. return 0;
65. }
66. /*
67. [root@localhost TestCode]# ./a.out
68. [in tri_process] sum=9
69. [in tri_control] sum=18
70. **********************************
71. [in tri_process] sum=9
72. in Alg_process..
73. [in tri_control] sum=18
74. in Alg_control..
75. */

此代码在ubuntu下运行还是有点问题出现两个类似的段错误，估计是野指针和未分配内存的缘故！

第一个解决：

ret->handle=(Alg_Handle)malloc(sizeof(Alg_Handle));

第二个：

我干脆把改了之后的完整代码贴上吧！

#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;

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);
}
void Alg_process(Alg_Handle handle)
{
struct triangle *ret= (struct triangle *)malloc(sizeof(struct triangle));
ret->handle=(Alg_Handle)malloc(sizeof(Alg_Handle));
ret->handle->fxns=(struct Alg_Fxn*)malloc(sizeof(struct Alg_Fxn));
ret->handle->fxns->process=(Alg_Handle *)malloc(sizeof(Alg_Handle));
ret->handle->fxns->process=tri_process;
ret=handle;
ret->handle->fxns->process(ret);
printf("in Alg_process.. \n");
}

void Alg_control(Alg_Handle handle)
{
struct triangle *ret= (struct triangle *)malloc(sizeof(struct triangle));
ret->handle=(Alg_Handle)malloc(sizeof(Alg_Handle));
ret->handle->fxns=(struct Alg_Fxn*)malloc(sizeof(struct Alg_Fxn));
ret->handle->fxns->control=(Alg_Handle *)malloc(sizeof(Alg_Handle));
ret->handle->fxns->control=tri_control;
ret->handle->fxns->control(ret);
//handle->fxns->control(handle);
printf("in Alg_control.. \n");
}
Alg_Fxn gfxns = {
tri_process,
tri_control,
};
int main()
{
struct triangle *ret= (struct triangle *)malloc(sizeof(struct triangle));
ret->a = 2;
ret->b = 3;
ret->c = 4;
ret->handle=(Alg_Handle)malloc(sizeof(Alg_Handle));
ret->handle->fxns=&gfxns;
Alg_Handle Handle= ret;
//第一种调用，注意结果
gfxns.process(Handle);
gfxns.control(Handle);
printf("\n**********************************\n");
//第二种调用，注意结果
Alg_process(Handle);//Handle
Alg_control(Handle);
//free(Handle);
return 0;

}