stamen

0 #include <cmath>

1 #include <cstddef>

2 #include <format>

3 #include <iostream>

4 #include <limits>

5

6 #include "demo_menu.hpp"

7

8 namespace example {

9

10 int menu_t::visit(const menu_t& menu)

11 {

12 const int sizei = static_cast<int>(menu.items.size());

13 const size_t dgts = static_cast<size_t>(std::log10(sizei)) + 1;

14 int choice = 0;

15

16 while (true)

17 {

18 std::cout << std::format("{}:\n", menu.title);

19 for (auto i = 0UL; i < menu.items.size(); i++)

20 {

21 std::cout << std::format(" {:{}}. {}\n", i, dgts, menu.items[i].prompt);

22 }

23

24 while (true)

25 {

26 std::cout << "Choose an option: ";

27 if (std::cin >> choice && choice >= -1 && choice < sizei)

28 {

29 if (choice == -1)

30 {

31 std::cout << "Choice: back\n";

32 return 1;

33 }

34

35 const auto uchoice = static_cast<size_t>(choice);

36 std::cout << "Choice: " << menu.items[uchoice].prompt << "\n\n";

37 const int res = menu.items[uchoice].callback(uchoice);

38

39 if (res < 2) break;

40 return res - 1;

41 }

42

43 if (std::cin.eof())

44 {

45 std::cerr << "encountered end of input!\n";

46 return std::numeric_limits<int>::max();

47 }

48

49 std::cin.clear();

50 std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');

51 std::cout << "Invalid option, please choose again!\n";

52 }

53

54 std::cout << '\n' << std::flush;

55 }

56

57 return 1;

58 }

59

60 int operation1(std::size_t /* unused */)

61 {

62 std::cout << "operation 1\n\n";

63 std::cout << "Some operation is done\n\n";

64 std::cout << std::flush;

65 return 1;

66 }

67

68 int operation2(std::size_t /* unused */)

69 {

70 std::cout << "operation 2\n";

71 std::cout << "Some other operation is done\n";

72 std::cout << std::flush;

73 return 1;

74 }

75

76 int operation3(std::size_t /* unused */)

77 {

78 std::cout << "operation 3\n";

79 std::cout << "Yet another operation is done\n";

80 std::cout << std::flush;

81 return 1;

82 }

83

84 int finish(std::size_t /* unused */)

85 {

86 std::cout << "finishing...\n";

87 std::cout << std::flush;

88 exit(0); // NOLINT

89 }

90

91 } // namespace example

92

93 int main()

94 {

95 example::menu_main(0);

96 return 0;

97 }