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  1. #include <iostream>
  2. #include <functional>
  3.  
  4. struct wrap
  5. {
  6. 	std::function<wrap ()> f;
  7. 	template<typename F>
  8. 	wrap(F f)
  9. 	: f(f)
  10. 	{
  11. 	}
  12. 	wrap operator()()
  13. 	{
  14. 		return f();
  15. 	}
  16. };
  17.  
  18. wrap menu_sub_1();
  19. wrap menu_sub_2();
  20. wrap menu_main()
  21. {
  22. 	std::cout
  23. 		<< "Main menu" << std::endl
  24. 		<< "1. Sub menu 1" << std::endl
  25. 		<< "2. Sub menu 2" << std::endl
  26. 		<< "3. Exit" << std::endl;
  27. 	int x;
  28. 	std::cin >> x;
  29. 	if(x == 1) return menu_sub_1;
  30. 	else if(x == 2) return menu_sub_2;
  31. 	else if(x == 3) std::exit(0);
  32. 	return menu_main;
  33. }
  34. wrap menu_sub_1()
  35. {
  36. 	std::cout
  37. 		<< "Sub menu 1" << std::endl
  38. 		<< "1. Back to main menu" << std::endl;
  39. 	int x;
  40. 	std::cin >> x;
  41. 	if(x == 1) return menu_main;
  42. 	return menu_sub_1;
  43. }
  44. wrap menu_sub_2()
  45. {
  46. 	std::cout
  47. 		<< "Sub menu 2" << std::endl
  48. 		<< "1. Back to main menu" << std::endl;
  49. 	int x;
  50. 	std::cin >> x;
  51. 	if(x == 1) return menu_main;
  52. 	return menu_sub_2;
  53. }
  54.  
  55. int main()
  56. {
  57. 	auto f = menu_main();
  58. 	while(true)
  59. 	{
  60. 		f = f();
  61. 	}
  62. }
  63.  
Success #stdin #stdout 0s 3464KB
comments (?)
stdin 
1
1
2
1
3
stdout 
Main menu
1. Sub menu 1
2. Sub menu 2
3. Exit
Sub menu 1
1. Back to main menu
Main menu
1. Sub menu 1
2. Sub menu 2
3. Exit
Sub menu 2
1. Back to main menu
Main menu
1. Sub menu 1
2. Sub menu 2
3. Exit
https://ideone.com/Bbv93E
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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