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）

1. #include <stdio.h>  
2. #include <stdlib.h>  
3. #include <string.h>  
4.   
5.   
6. typedef struct Alg_Obj{  
7.     struct Alg_Fxn* fxns;  
8. }Alg_Obj;  
9.   
10. typedef Alg_Obj *Alg_Handle;  
11.   
12. typedef struct Alg_Fxn{  
13.     void (*process)(Alg_Handle handle);  
14.     void (*control)(Alg_Handle handle);  
15. }Alg_Fxn;  
16.   
17. void Alg_process(Alg_Handle handle)  
18. {  
19.     handle->fxns->process(handle);  
20.     printf("in Alg_process..  ");  
21. }  
22.   
23. void Alg_control(Alg_Handle handle)  
24. {  
25.     handle->fxns->control(handle);  
26.     printf("in Alg_control..  ");  
27. }  
28.   
29.   
30. struct triangle{  
31.     Alg_Handle handle;  
32.     int a;  
33.     int b;  
34.     int c;  
35. };  
36. void tri_process(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_process] sum=%d ",a+b+c);  
43. }  
44. void tri_control(Alg_Handle handle)  
45. {  
46.     struct triangle *t = (struct triangle*)handle;   
47.     int a = t->a;  
48.     int b = t->b;  
49.     int c = t->c;  
50.     printf("  [in tri_control] sum=%d ",(a+b+c)*2);  
51. }  
52.   
53. Alg_Fxn gfxns = {  
54.     tri_process,  
55.     tri_control,      
56. };  
57.   
58.   
59. int main()  
60. {  
61.     struct triangle *ret = (struct triangle*)malloc(sizeof(struct triangle));  
62.     ret->handle->fxns=&gfxns;  
63.     ret->a = 2;  
64.     ret->b = 3;  
65.     ret->c = 4;  
66.       
67.     Alg_Handle Handle= (Alg_Handle)ret;  
68.     //第一种调用，注意结果  
69.     gfxns.process(Handle);  
70.     gfxns.control(Handle);  
71.   
72.     printf(" ********************************** ");  
73.       
74.     //第二种调用，注意结果  
75.     Alg_process(Handle);  
76.     Alg_control(Handle);  
77.   
78.     free(Handle);  
79.     return 0;  
80.       
81. }  
82. /* 
83. [root@localhost TestCode]# ./a.out  
84.   [in tri_process] sum=9 
85.   [in tri_control] sum=18 
86.  
87. ********************************** 
88.   [in tri_process] sum=9 
89. in Alg_process..  
90.   [in tri_control] sum=18 
91. in Alg_control..  
92.  
93. */  

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 ",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 ",(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.. ");
}

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.. ");
}
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(" ********************************** ");
//第二种调用，注意结果
Alg_process(Handle);//Handle
Alg_control(Handle);
//free(Handle);
return 0;

}