std::optional

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std::optional:

*Introduction

*std::optional as return value

*value_or

*Using optionals to represent the absence of a value

*Using optionals to represent the failure of a function

Table Of Contents

0Getting started

1Literals

2Basic type keywords

3Operator precedence

4Floating point arithmetic

5Bit operators

6Bit manipulation

7Bit fields

8Arrays

9Flow control

10const keyword

11Loops

12mutable keyword

13friend keyword

14keywords

15Variable declaration keywords

16auto keyword

17Pointers

18Type keywords (class, enum, struct, union)

19Classes / structs

20std::string

21Enumeration

22std::atomic

23std::vector

24std::array

25std::pair

26std::map

27std::unordered_map

28std::set and std::multiset

29std::any

30std::variant

31std::optional

32std::integer_sequence

33std::function

34std::forward_list

35std::iomanip

36Iterators

37Basic I/O

38File I/O

39Streams

40Stream manipulators

41Metaprogramming

42Returning multiple values from a function

43References

44Polymorphism

45Value and reference semantics

46Function call by value vs. by reference

47Copying vs assignment

48Pointers to class / struct members

49The this pointer

50Smart pointers

51Unions

52Templates

53Namespaces

54Function overloading

55Operator overloading

56Lambdas

57Threading

58Value categories

59Preprocessor

60SFINAE

61Rule of three, five and zero

62RAII

63Exceptions

64Implementation-defined behavior

65Special member functions

66Random numbers

67Sorting

68Regular expressions

69Perfect forwarding

70Virtual member functions

71Undefined behavior

72Overload resolution

73Move semantics

74Pimpl idiom

75Copy elision

76Fold expressions

77Unnamed types

78Singleton

79ISO C++ Standard

80User-defined literals

81Type erasure

82Memory management

83Explicit type conversions

84RTTI

85Standard library algorithms

86Expression templates

87Scopes

88Atomic types

89static assert

90constexpr

91Date and time with std::chrono

92Trailing return type

93Function template overloading

94Common compile linker errors

95Design patterns

96Optimizations

97Compiling and building

98Type traits

99One definition rule

100Unspecified behavio

101Argument dependent name lookup

102Attributes

103Internationalization

104Profiling

105Return type covariance

106Non-static member functions

107Recursion

108Callable objects

109Constant class member functions

110C++ vs. C++ 11 vs C++ 17

111Inline functions

112Client server examples

113Header files

114Const correctness

115Refactoring techniques

116Parameter packs

117Iteration

118type deduction

119C++ 11 memory model

120Build systems

121Concurrency with OpenMP

122Type inference

123Resource management

124Storage class specifiers

125Alignment

126Inline variables

127Linkage specifications

128Curiusly recurring template pattern

129Using declaration

130Typedef and type aliases

131Layout of object types

132C incompatibilities

133Optimization

134Semaphore

135Thread synchronization

136Debugging

137Futures and promises

138More undefined behaviors

139Mutexes

140Recursive mutex

141Unit testing

142decltype

143Digit separators

144C++ Containers

145Arithmetic meta-programming

146Contributors