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  1. #include <iostream>
  2. #include <string>
  3. #include <string_view>
  4.  
  5. constexpr bool validate(std::string_view view, int n)
  6. {
  7. 	int i = 0;
  8. 	for (auto& c : view)
  9. 	{
  10. 		if (c == '%')
  11. 		{
  12. 			i++;
  13. 		}
  14. 	}
  15. 	return i == n;
  16. }
  17.  
  18. template<class StrLiteral, class ...Vars>
  19. void fmt(StrLiteral str, const Vars&... args)
  20. {
  21. 	constexpr std::string_view view = str();
  22.  
  23. 	static_assert(validate(view, sizeof...(args)), "Wrong format");
  24.  
  25. 	printf(view.data(), args...);
  26. }
  27.  
  28. template<class ...Vars>
  29. void fmt(std::string str, const Vars& ... args)
  30. {
  31. 	printf(str.c_str(), args...);
  32. }
  33.  
  34. #define _F(str) []() { return str; }
  35.  
  36. void main()
  37. {
  38. 	fmt(_F("compile %d\n"), 555);
  39. 	fmt(std::string("runtime no check %d\n"), 555);
  40. 	fmt(_F("compile no args\n"));
  41. 	//fmt(_F("compile error\n"), 555);
  42. 	return;
  43. }
Compilation error #stdin compilation error #stdout 0s 0KB
comments (?)
stdin 
Standard input is empty
compilation info 
prog.cpp:3:23: fatal error: string_view: No such file or directory
 #include <string_view>
                       ^
compilation terminated.
stdout 
Standard output is empty
https://ideone.com/bbn6kB
language:
C++14 (gcc 8.3)
created:
4 years ago
visibility:
public

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