借此可小小地实现C的面向对象

代码 
 1 #include <stdio.h>   
 2 #include <malloc.h>   
 3 #include <memory.h>   
 4  #define DECLARATION int (*ptr)(int x,int y)   
 5 #define DEFINITION(x,y) ptr(x,y)   
 6 int sum(int x,int y){    
 7     return(x+y);    
 8 }   
 9 void main()   
10 {   
11     int a,b,c;   
12         typedef struct {   
13         int r;   
14         DECLARATION;   
15             //int (*ptr)(int x,int y);   
16      } mystr;   
17     scanf("%d,%d",&a,&b);   
18     //////////////////////////////////   
19     //mystr stru;   
20     //stru.ptr=sum;   
21     //c=stru.ptr(a,b);   
22     //printf("a=%d,b=%d,sum=%d\n",a,b,c);   
23     ///////////////////////////////////   
24   
25     typedef mystr *struc;   
26     struc stru;   
27     stru=(struc)malloc(sizeof(mystr));   
28     memset(stru,0,sizeof(mystr));   
29     stru->ptr=sum;   
30     c=stru->DEFINITION(a,b);   
31     //c=stru->ptr(a,b);   
32     printf("a=%d,b=%d,sum=%d\n",a,b,c);   
33     memset(stru,0,sizeof(mystr));   
34         free(stru);   
35 }   
36