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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3.  
  4. typedef enum {
  5. 	INT,
  6. 	STR,
  7. } type;
  8.  
  9. typedef struct {
  10. 	type type;
  11. 	union {
  12. 		char *s;
  13. 		int i;
  14. 	};
  15. } variant_t;
  16.  
  17. #define VARIANT(x) _Generic((x), \
  18. 	int: ((variant_t){.type = INT, .i = x}), \
  19. 	char*: ((variant_t){.type = STR, .s = x}) \
  20. )
  21.  
  22. void foo_int(int i)
  23. {
  24. 	printf("Integer %d\n", i);
  25. }
  26.  
  27. void foo_str(char *s)
  28. {
  29. 	printf("String \"%s\"\n", s);
  30. }
  31.  
  32. #define foo(x) (_Generic((x), \
  33. 	int: foo_int, \
  34. 	char*: foo_str \
  35. )(x))
  36.  
  37. void dynamic_foo(variant_t pitux)
  38. {
  39. 	switch (pitux.type) {
  40. 		case INT: foo(pitux.i); break;
  41. 		case STR: foo(pitux.s); break;
  42. 		default: error("Error!"); break;
  43. 	}
  44. }
  45.  
  46. int main(void)
  47. {
  48. 	for (int i = 0; i < 10; ++i) {
  49. 		dynamic_foo(rand() & 1 ? VARIANT(42): VARIANT("forty two"));
  50. 	}
  51. 	return 0;
  52. }
Success #stdin #stdout 0s 4284KB
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stdin
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Standard input is empty
stdout
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Integer 42
String "forty two"
Integer 42
Integer 42
Integer 42
Integer 42
String "forty two"
String "forty two"
Integer 42
Integer 42
https://ideone.com/fuFg1H
language:
C (gcc 8.3)
created:
6 years ago
visibility:
public

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