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  1. #include <stdio.h>
  2. #include <stddef.h>
  3.  
  4. typedef struct Node {
  5. 	int a;
  6. 	int b;
  7. 	int c;
  8. } Node;
  9.  
  10. #define SET_MEMBER(obj, member_name, value)\
  11. 	set_member(value, (void*)((char *)obj + offsetof(Node, member_name)))\
  12. /**/
  13.  
  14. void set_member(int value, int *pointer){//or use memcpy
  15. 	*pointer = value;
  16. }
  17.  
  18. static inline void print_Node(Node *node);
  19.  
  20. int main(void){
  21. 	Node mynode = {.a = 0, .b = 45, .c = 64};
  22.  
  23. 	print_Node(&mynode);
  24. 	SET_MEMBER(&mynode, a, 1);
  25. 	print_Node(&mynode);
  26. }
  27.  
  28. static inline void print_Node(Node *node){
  29. 	printf("{ a:%d, b:%d, c:%d }\n", node->a, node->b, node->c);
  30. }
  31.  
Success #stdin #stdout 0s 9432KB
comments (?)
stdin
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Standard input is empty
stdout
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{ a:0, b:45, c:64 }
{ a:1, b:45, c:64 }
https://ideone.com/x2GxCE
language:
C99 (gcc 8.3)
created:
8 years ago
visibility:
public

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