C++11 —— 奇怪這真的是 C++ 嗎

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1. C++11 حոഝਅతੋ C++ 䆩ʁ ࢿ؅ҰA ֲࢠ℄
2. ࠓ೔ᔒ༗ Live DEMO
3. • ઌલඃ᜝࡞ C++0xɼଈ ISO/IEC 14882:2011ɼੋ໨લత C++ ఔࣜޠݴతਖ਼ࣜඪ४ɻ༻Ҏऔ୅ C++98 Ҏٴ C++03ɻ • ৽తඪ४แؚ֩৺ޠݴత৽ޭೳɼฒ׌Ꮇల C++ ඪ४ఔࣜ ݿɼซೖྃେ෦෼త C++ Technical Report 1 ఔࣜݿ (Ꮠላ తಛघവࣜআ֎)ɻ • ࠜᎦ Bjarne Stroustrup (C++ త૑࢝ਓ) දࣔɼ৽తඪ४ሡ زݷ 100% ૬༰ԙݱ༗ඪ४ɻ w w C++11
4. • C++11
 http://zh.wikipedia.org/wiki/C%2B%2B11 • C++ TR1
 http://zh.wikipedia.org/wiki/C%2B%2B_Technical_Report_1 • C++ Boost
 http://zh.wikipedia.org/wiki/Boost_C%2B%2B_Libraries Wikipedia
5. • C++
 template class std::vector<MyClass>; • ။ࡏฤᩄظ۩ݱԽ
 ʢinstantiateɼመ࡞ machine codeʣ ֎෦໛൘ Extern template
6. 1. template <typename T> 2. class MyClass { 3. public: 4. void print(T data) { 5. std::cout << data << std::endl; 6. } 7. }; ໛൘ Template
7. 1. template <typename T> 2. class MyClass { 3. public: 4. void print(T data) { 5. std::cout << data << std::endl; 6. } 7. }; ໛൘ Template
8. 1. template <typename T> 2. class MyClass { 3. public: 4. void print(T data) { 5. std::cout << data << std::endl; 6. } 7. }; ໛൘ Template
9. 1. template <typename T> 2. class MyClass { 3. public: 4. void print(T data) { 5. std::cout << data << std::endl; 6. } 7. }; ໛൘ Template
10. • MyClass.h : template class MyClass<T> ۩ݱԽ • A.cpp : template class MyClass<int> ۩ݱԽ • B.cpp : template class MyClass<int> ۩ݱԽ http://goo.gl/ASpqXx http://zevoid.blogspot.tw/2012/04/c11-extern-template.html
11. • MyClass.h : template class MyClass<T> ۩ݱԽ • A.cpp : template class MyClass<int> ۩ݱԽ • B.cpp : template class MyClass<int> ۩ݱԽ http://goo.gl/ASpqXx http://zevoid.blogspot.tw/2012/04/c11-extern-template.html
12. • MyClass.h : template class MyClass<T> ۩ݱԽ • A.cpp : template class MyClass<int> ۩ݱԽ • B.cpp : template class MyClass<int> ۩ݱԽ http://goo.gl/ASpqXx http://zevoid.blogspot.tw/2012/04/c11-extern-template.html ॏෳ
13. • C++11
 extern template class std::vector<MyClass>; • ။ࡏฤᩄظ۩ݱԽ
 ҆҆㟬޷զੋۭന ֎෦໛൘ Extern template
14. • C++11
 extern template class std::vector<MyClass>; • ။ࡏฤᩄظ۩ݱԽ
 ࿈݁࣌ਘፙቮ༗త୅ᛰိ࢖༻ ֎෦໛൘ Extern template
15. • like this: • extern int globalNumber; ֎෦໛൘ Extern template
16. • C++
 int[] numbers = {1, 2, 3, 4}; • C++
 std::vector<int> numbers = {1, 2, 3, 4}; ॳ࢝Խ۲ྻ Initializer lists
17. • C++
 int[] numbers = {1, 2, 3, 4}; • C++
 std::vector<int> numbers = {1, 2, 3, 4}; ॳ࢝Խ۲ྻ Initializer lists
18. • std::initializer_list<T> ॳ࢝Խ۲ྻ Initializer lists
19. 1. class SequenceClass 2. { 3. public: 4. SequenceClass(std::initializer_list<int> list); 5. }; ॳ࢝Խ۲ྻ Initializer lists
20. • C++11
 SequenceClass someVar = {1, 4, 5, 6};
 std::vector<int> numbers = {1, 2, 3, 4};
 std::vector<std::string> v = { "this", "is", "awesome" }; ॳ࢝Խ۲ྻ Initializer lists
21. • ୈҰڃత C++11 ඪ४ఔࣜݿܕผɻ • ୞ೳៃ༝ฤᩄثಁա {…} ޠ๏ඃᯩଶ஍ݐߏ ɻ • ҰៃݐߏศՄෳ੡ (copy-by-reference)ɻ • ሱԙৗᏐɼҰ୴ඃݐཱɼଖ੒һۉෆೳඃվᏓɼ੒һ தతࢿྉ໵ෆೳඃᏓಈɻ std::initializer_list<T>
22. • void wantSomeFloats(std::initializer_list<float> list); • wantSomeFloats({1.0f, -3.45f, -0.4f}); std::initializer_list<T>
23. • C++
 ୞༗ struct ࿨ POD ܕผೳ夠࢖༻ {…} ॳ࢝Խ
 ౷Ұతॳ࢝Խ Uniform initialization
24. 1. struct BasicStruct 2. { 3. int x; 4. float y; 5. }; 6. BasicStruct var1{5, 3.2f}; ౷Ұతॳ࢝Խ Uniform initialization
25. • C++11
 ఏڙҰछ౷Ұతޠ๏ိॳ࢝Խ೚ҙత෺݅ɼ
 ሏᎷॆྃॳ࢝Խ۲ྻޠ๏ ౷Ұతॳ࢝Խ Uniform initialization
26. 1. struct AltStruct 2. { 3. AltStruct(int _x, float _y) : x(_x), y(_y) {} 4. private: 5. int x; 6. float y; 7. }; 8. AltStruct var2{2, 4.3f}; ౷Ұతॳ࢝Խ Uniform initialization
27. 1. struct IdString 2. { 3. std::string name; 4. int identifier; 5. }; 6. IdString var3{"SomeName", 4}; ౷Ұతॳ࢝Խ Uniform initialization
28. 1. struct IdString 2. { 3. std::string name; 4. int identifier; 5. }; 6. IdString var3{"SomeName", 4}; ౷Ұతॳ࢝Խ Uniform initialization
29. 1. struct IdString 2. { 3. std::string name; 4. int identifier; 5. }; 6. IdString var3{"SomeName", 4}; ౷Ұతॳ࢝Խ Uniform initialization const char *
30. 1. IdString GetString() 2. { 3. return {"SomeName", 4}; 4. } ౷Ұతॳ࢝Խ Uniform initialization
31. 1. IdString GetString() 2. { 3. return {"SomeName", 4}; 4. } ౷Ұతॳ࢝Խ Uniform initialization ။ࣗಈॳ࢝Խ IdString
32. • C++
 for (
 std::vector<int>::const_iterator itr = v.cbegin();
 itr != v.cend();
 ++itr
 ) {…} ܕผਪಋ Type inference
33. • C++11
 for (
 auto itr = v.cbegin();
 itr != v.cend();
 ++itr
 ) {…} ܕผਪಋ Type inference
34. • C++11
 for (
 auto itr = v.cbegin();
 itr != v.cend();
 ++itr
 ) {…} ܕผਪಋ Type inference Magic !
35. • C++
 int array[5] = {1, 2, 3, 4, 5};
 for (int i = 0; i < sizeof(my_array); i++) {…} Range-based for loop
36. • C++11
 int array[5] = {1, 2, 3, 4, 5};
 for (int &x : array) {…} Range-based for loop
37. • C++11
 int array[5] = {1, 2, 3, 4, 5};
 for (auto &x : array) {…} Range-based for loop
38. • C++
 …? Lambda
39. • C++11
 [](int x, int y) { return x + y; }
 [](int x, int y) -> int { int z = x + y; return z + x; } Lambda
40. • C++11
 [](int x, int y) { return x + y; }
 [](int x, int y) -> int { int z = x + y; return z + x; } Lambda auto declared
41. • C++11
 [](int x, int y) { return x + y; }
 [](int x, int y) -> int { int z = x + y; return z + x; } Lambda
42. • [] // ᔒ༗Ҿ༻೚Կ֎෦ᏓᏐɻ࢖༻ະఆٛᏓᏐ။ಋகࡨޡɻ • [x, &y] // x Ҏၚ值ํࣜၚೖ(༬ઃ)ɼy Ҏၚჩߟํࣜၚೖɻ • [&] // ೚Կඃ࢖༻౸త֎෦ᏓᏐօᯅࣜ஍ҎჩߟํࣜՃҎҾ༻ɻ • [=] // ೚Կඃ࢖༻౸త֎෦ᏓᏐօᯅࣜ஍Ҏၚ值ํࣜՃҎҾ༻ɻ • [&, x] // x Ҏၚ值ํࣜՃҎҾ༻ɻଖᰨᏓᏐҎჩߟํࣜՃҎҾ༻ɻ • [=, &z] // z ҎჩߟํࣜՃҎҾ༻ɻଖᰨᏓᏐҎၚ值ํࣜՃҎҾ༻ɻ Lambda
43. 1. std::vector<int> someList; 2. int total = 0; 3. std::for_each(someList.begin(), someList.end(), [&total](int x) { 4. total += x; 5. }); 6. std::cout << total; Lambda
44. 1. std::vector<int> someList; 2. int total = 0; 3. std::for_each(someList.begin(), someList.end(), [&total](int x) { 4. total += x; 5. }); 6. std::cout << total; Lambda
45. • C++11
 [](SomeType *typePtr) {
 typePtr->SomePrivateMemberFunction(); 
 };
 [this]() { this->SomePrivateMemberFunction(); }; Lambda in Class
46. 1. klass.config([](Klass::config &config) { 2. config.key = value; 3. }); Lambda in Class ෆੋ Live త DEMO
47. • ᫚઀ (delegation) ෺݅ݐߏతվྑ Object construction improvement
48. 1. class SomeType { 2. int number; 3. string name; 4. SomeType( int i, string& s ) : number(i), name(s) {} 5. public: 6. SomeType( ) : SomeType( 0, "invalid" ) {} 7. SomeType( int i ) : SomeType( i, "guest" ) {} 8. SomeType( string& s ) : SomeType( 1, s ){ PostInit(); } 9. }; ෺݅ݐߏతվྑ Object construction improvement
49. • खಈ៺ঝجఈܕผతݐߏࣜ ෺݅ݐߏతվྑ Object construction improvement
50. 1. class BaseClass { 2. public: 3. BaseClass(int iValue); 4. }; 5. class DerivedClass : public BaseClass { 6. public: 7. using BaseClass::BaseClass; 8. }; ෺݅ݐߏతվྑ Object construction improvement
51. • ߋํศత੒һॳ࢝Խ༬ઃ值 ෺݅ݐߏతվྑ Object construction improvement
52. 1. class MyClass { 2. int number = 12; 3. public: 4. MyClass() {}; 5. }; ෺݅ݐߏతվྑ Object construction improvement
53. 1. class MyClass { 2. int number = 12; 3. public: 4. MyClass() {}; 5. }; ෺݅ݐߏతվྑ Object construction improvement Not in C++
54. 1. class MyClass { 2. int number; 3. public: 4. MyClass() : number(12) {}; 5. }; ෺݅ݐߏతվྑ Object construction improvement C++
55. 1. class MyClass { 2. int number = 12; 3. public: 4. MyClass() {}; 5. }; ෺݅ݐߏతվྑ Object construction improvement C++11
56. 1. class BaseClass { 2. public: 3. BaseClass(int iValue); 4. }; 5. class DerivedClass : public BaseClass { 6. public: 7. using BaseClass::BaseClass; 8. }; ෺݅ݐߏతվྑ Object construction improvement
57. 1. struct Base { 2. virtual void some_func(); 3. }; 4. struct Derived : Base { 5. void some_func(); 6. }; ᰖࣜ㐘വࣜॏࡌ Explicit overrides and final .
58. 1. struct Base { 2. virtual void some_func(); 3. }; 4. struct Derived : Base { 5. void some_func(); 6. }; ᰖࣜ㐘വࣜॏࡌ Explicit overrides and final . ॏࡌ (Override)ʁ ଟܕ (Polymorphism)ʁ
59. 1. struct Base { 2. virtual void some_func(float); 3. }; 4. struct Derived : Base { 5. virtual void some_func(int) override; 6. virtual void some_func(float) override; 7. }; ᰖࣜ㐘വࣜॏࡌ Explicit overrides and final .
60. 1. struct Base { 2. virtual void some_func(float); 3. }; 4. struct Derived : Base { 5. virtual void some_func(int) override; 6. virtual void some_func(float) override; 7. }; ᰖࣜ㐘വࣜॏࡌ Explicit overrides and final .
61. 1. struct Base { 2. virtual void some_func(float); 3. }; 4. struct Derived : Base { 5. virtual void some_func(int) override; 6. virtual void some_func(float) override; 7. }; ᰖࣜ㐘വࣜॏࡌ Explicit overrides and final .
62. 1. struct Base1 final { }; 2. struct Derived1 : Base1 { }; 3. struct Base2 { 4. virtual void f() final; 5. }; 6. struct Derived2 : Base2 { 7. void f(); 8. }; ᰖࣜ㐘വࣜॏࡌ Explicit overrides and final .
63. 1. struct Base1 final { }; 2. struct Derived1 : Base1 { }; 3. struct Base2 { 4. virtual void f() final; 5. }; 6. struct Derived2 : Base2 { 7. void f(); 8. }; ᰖࣜ㐘വࣜॏࡌ Explicit overrides and final .
64. • override ᢛ final ౎ෆੋޠݴ᮫ݤࣈ (keyword) ᰖࣜ㐘വࣜॏࡌ Explicit overrides and final .
65. • C
 NULL
 0
 ((void*)0) • C++
 NULL
 0 • C++11
 nullptr (nullptr_t ܕผɼෆՄඃ᫚׵੒੔Ꮠɼ໵ෆೳൺֱ)
 0 ۭࢦඪ Null pointer constant
66. 1. void foo(char *); 2. void foo(int); 3. foo(NULL); ۭࢦඪ Null pointer constant
67. 1. void foo(char *); 2. void foo(int); 3. foo(NULL); ۭࢦඪ Null pointer constant 0
68. 1. void foo(char *); 2. void foo(int); 3. foo(NULL); ۭࢦඪ Null pointer constant 0
69. 1. void foo(char *); 2. void foo(int); 3. foo(nullptr); ۭࢦඪ Null pointer constant
70. 1. void foo(char *); 2. void foo(int); 3. foo(nullptr); ۭࢦඪ Null pointer constant
71. • C++ ۭന
 ෆੋܕผ҆શత (not type-safe)
 all enums are integer (could be compared)㠷
 ๫࿐ԙҰൠൣᅴத ڧܕผྻᎯ Strongly typed enumerations.
72. 1. enum Side{ Right, Left }; 2. enum Thing{ Wrong, Right }; ڧܕผྻᎯ Strongly typed enumerations.
73. 1. enum Side{ Right, Left }; 2. enum Thing{ Wrong, Right }; ڧܕผྻᎯ Strongly typed enumerations. Not in C++
74. 1. enum Side{ Right, Left }; 2. enum Thing{ Wrong, Right }; ڧܕผྻᎯ Strongly typed enumerations. Not in C++11
75. 1. enum class Enumeration /* : int */ 2. { 3. Val1, 4. Val2, 5. Val3 = 100, 6. Val4 /* = 101 */, 7. }; ڧܕผྻᎯ Strongly typed enumerations.
76. • C++11
 લஔᡎ໌ (forward declaration) 
 ྻᎯྨ (classification of enumeration)
 ܕผ҆શ (type-safe)
 ޠኮൣᅴ (scoping) ఆٛԙྻᎯܕผత໊᜝ൣᅴத ڧܕผྻᎯ Strongly typed enumerations.
77. • C++11
 લஔᡎ໌ (forward declaration) 
 ྻᎯྨ (classification of enumeration)
 ܕผ҆શ (type-safe)
 ޠኮൣᅴ (scoping) ఆٛԙྻᎯܕผత໊᜝ൣᅴத ڧܕผྻᎯ Strongly typed enumerations. Enumeration::Val4 == 101
78. • C++11
 લஔᡎ໌ (forward declaration) 
 ྻᎯྨ (classification of enumeration)
 ܕผ҆શ (type-safe)
 ޠኮൣᅴ (scoping) ఆٛԙྻᎯܕผత໊᜝ൣᅴத ڧܕผྻᎯ Strongly typed enumerations. Enumeration::Val4 == 101 enum class Enum2 : unsigned int {Val1, Val2}; ҝྫ Enum2::Val1 ੋ༗ҙٛతදࣔ๏ɼ ࣕᄸᘐత Val1 ଇ൱ɻ
79. 1. enum Enum1; 2. enum Enum2 : unsigned int; 3. enum class Enum3; 4. enum class Enum4: unsigned int; 5. enum Enum2 : unsigned short; ڧܕผྻᎯ Strongly typed enumerations. લஔᡎ໌ (forward declaration)
80. 1. enum Enum1; 2. enum Enum2 : unsigned int; 3. enum class Enum3; 4. enum class Enum4: unsigned int; 5. enum Enum2 : unsigned short; ڧܕผྻᎯ Strongly typed enumerations. લஔᡎ໌ (forward declaration) ແ๏൑ผେখ
81. 1. enum Enum1; 2. enum Enum2 : unsigned int; 3. enum class Enum3; 4. enum class Enum4: unsigned int; 5. enum Enum2 : unsigned short; ڧܕผྻᎯ Strongly typed enumerations. લஔᡎ໌ (forward declaration) ແ๏൑ผେখ Enum2 ቮඃᡎ໌ҝ unsigned int
82. • C++
 Ұ཯ሡ ">>" ࢹҝӈҠӡࢉࢠ
 std::vector<std::pair<int, int>>
 std::vector<std::pair<int, int> > • C++11
 ༏ઌղੳӈׅ֯ᥒҝᒬ൘ҾᏐత݁ଋූᥒ
 std::vector<std::pair<int, int>>
 std::vector<std::pair<int, int> > ׅ֯ᥒ >>
83. 1. template<bool bTest> SomeType; 2. std::vector<SomeType<1>2>> x1; 3. std::vector<SomeType<(1>2)>> x2; ׅ֯ᥒ >>
84. 1. template<bool bTest> SomeType; 2. std::vector<SomeType<1>2>> x1; 3. std::vector<SomeType<(1>2)>> x2; ׅ֯ᥒ >> SomeType<true> 2>
85. 1. template<bool bTest> SomeType; 2. std::vector<SomeType<1>2>> x1; 3. std::vector<SomeType<(1>2)>> x2; ׅ֯ᥒ >> SomeType<true> 2>
86. 1. template<bool bTest> SomeType; 2. std::vector<SomeType<1>2>> x1; 3. std::vector<SomeType<(1>2)>> x2; ׅ֯ᥒ >> SomeType<true> 2> SomeType<false>
87. 1. template< typename A, typename B, int num> 2. class SomeType; 3. 4. template< typename B> 5. typedef SomeType<OtherType, B, 5> Name; ໛൘తผ໊ Alias templates Not in C++
88. 1. template< typename A, typename B, int num> 2. class SomeType; 3. 4. template< typename B> 5. using Name = SomeType<OtherType, B, 5>; ໛൘తผ໊ Alias templates C++11
89. • C++
 typedef void (*PFD)(double); • C++11
 typedef void (*PFD)(double);
 using PFD = void (*)(double); ໛൘తผ໊ Alias templates
90. • C++11
 template<typename... Values> class tuple; ෆఆ௕ჩᏐ໛൘ Variadic templates
91. 1. template<> 2. struct count<> { 3. static const int value = 0; 4. }; 5. template<typename T, typename... Args> 6. struct count<T, Args...> { 7. static const int value = 1 + count<Args...>::value; 8. }; ෆఆ௕ჩᏐ໛൘ Variadic templates
92. • C++
 "TEXT" (const char *)
 L"TEXT" (const wchar_t *) • C++11
 u8"I'm a UTF-8 string." (const char *)
 u"This is a UTF-16 string." (const char16_t *)
 U"This is a UTF-32 string." (const char32_t *)
 u8"This is a Unicode Character: \u2018."
 u"This is a bigger Unicode Character: \u2018."
 U"This is a Unicode Character: \u2018." ৽తࣈ۲ࣈ໘值 New string literals
93. • C++11
 R"(The String Data \ Stuff " )"
 R"delimiter(The String Data \ Stuff " )delimiter" ৽తࣈ۲ࣈ໘值 New string literals
94. 1. struct SomeType { OtherType member; }; 2. sizeof(SomeType::member); sizeof