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  1. #include <array>
  2. //#include <initializer_list>
  3. #include <algorithm>
  4. template<class T,std::size_t N>
  5. class ConstexprVector {
  6. 	T Buff[N]{};
  7. 	std::size_t C = 0;
  8. public:
  9.  
  10. 	typedef T ValueType;
  11. 	typedef typename T* Iterator;
  12. 	typedef typename T const* ConstIterator;
  13. 	constexpr ConstexprVector(){};
  14. 	constexpr explicit ConstexprVector(const std::initializer_list<T>& L) {
  15. 		std::size_t V = 0;
  16. 		auto it1 = L.begin();
  17. 		auto it2 = &Buff[0];
  18. 		for (it1, it2; L.end() != it1&&it2 != &Buff[N]; it1++, it2++) {
  19. 			*it2 = *it1;
  20. 			V++;
  21. 		}
  22. 		C = V;
  23. 	}
  24. 	template<class Iter>
  25. 	constexpr explicit ConstexprVector(Iter Beg,Iter End) {
  26. 		std::size_t V = 0;
  27. 		auto it1 = Beg;
  28. 		auto it2 = &Buff[0];
  29. 		for (it1, it2; End != it1&&it2 != &Buff[N]; it1++, it2++) {
  30. 			*it2 = *it1;
  31. 			V++;
  32. 		}
  33. 		C = V;
  34. 	}
  35. 	constexpr std::size_t Size() const{
  36. 		return C;
  37. 	}
  38. 	constexpr std::size_t MaxSize() const {
  39. 		return N;
  40. 	}
  41. 	constexpr bool PushBack(const T& In) {
  42. 		if (C >= N) return false;
  43. 		Buff[C] = In;
  44. 		C++;
  45. 		return true;
  46. 	}
  47. 	/** /
  48. 	template<class... A>
  49. 	constexpr bool EmplaceBack(const A& ...In) {
  50. 		if (C >= Buff.size()) return false;
  51. 		Buff[C] = T(In...);
  52. 		C++;
  53. 		return true;
  54. 	}
  55. 	/**/
  56. 	constexpr bool PopBack() {
  57. 		if (C == 0)return false;
  58. 		//Buff[C]~T();
  59. 		C--;
  60. 		return true;
  61. 	}
  62.  
  63. 	constexpr bool Clear() {
  64. 		while (PopBack());
  65. 		return true;
  66. 	}
  67.  
  68. 	constexpr Iterator begin() {
  69. 		return Buff;
  70. 	}
  71.  
  72. 	constexpr ConstIterator begin() const {
  73. 		return &Buff[0];
  74. 	}
  75. 	constexpr Iterator end() {
  76. 		return Buff+C;
  77. 	}
  78. 	constexpr ConstIterator end() const {
  79. 		return Buff+C;
  80. 	}
  81. 	constexpr T& operator[](std::size_t idx) {
  82. 		int A = 0;
  83. 		if (Size() <= idx) A = 1/A;//kill?
  84.  
  85. 		return Buff[idx];
  86. 	}
  87. 	constexpr const T& operator[](std::size_t idx) const {
  88. 		int A = 0;
  89. 		if (Size() <= idx) A = 1/A;//kill?
  90.  
  91. 		return Buff[idx];
  92. 	}
  93. };
  94.  
  95. #include <iostream>
  96. #include <cstdint>
  97.  
  98. //#include "ConstexprVector.h"
  99.  
  100. typedef ConstexprVector<std::uint64_t, 128> DType;
  101. constexpr std::uint64_t Calc2(const DType& D) {
  102. 	std::uint64_t C = 0;
  103. 	for (auto& o:D) {
  104. 		C += o;
  105. 	}
  106.  
  107. 	return C;
  108. }
  109. constexpr std::uint64_t Calc(const DType& D) {
  110. 	std::uint64_t C = 0;
  111. 	for (std::size_t i = 0; i < D.Size();i++) {
  112. 		C += D[i];
  113. 	}
  114.  
  115. 	return C;
  116. }
  117.  
  118. constexpr DType Add(const DType& D, DType::ValueType V) {
  119. 	DType R(D.begin(), D.end());
  120. 	R.PushBack(V);
  121.  
  122. 	return R;
  123.  
  124. }
  125. int main() {
  126. 	constexpr DType D{ 1,2,3,4,5 };
  127. 	constexpr std::uint64_t R = Calc(D);
  128. 	constexpr std::uint64_t R2 = Calc2(D);
  129. 	constexpr DType D2=	Add(D, 6);
  130. 	constexpr std::uint64_t R3 = Calc(D2);
  131. 	std::cout << R << std::endl;
  132. 	std::cout << R3 << std::endl;
  133. 	return true;
  134. }
Compilation error #stdin compilation error #stdout 0s 0KB
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Standard input is empty
compilation info 
prog.cpp:11:19: error: expected nested-name-specifier before ‘T’
  typedef typename T* Iterator;
                   ^
prog.cpp:11:19: error: expected ‘;’ at end of member declaration
prog.cpp:11:19: error: declaration of ‘typedef int ConstexprVector<T, N>::T’ shadows template parameter
prog.cpp:4:10: note: template parameter ‘T’ declared here
 template<class T,std::size_t N>
          ^~~~~
prog.cpp:11:22: error: ISO C++ forbids declaration of ‘Iterator’ with no type [-fpermissive]
  typedef typename T* Iterator;
                      ^~~~~~~~
prog.cpp:12:19: error: expected nested-name-specifier before ‘T’
  typedef typename T const* ConstIterator;
                   ^
prog.cpp:12:19: error: expected ‘;’ at end of member declaration
prog.cpp:12:19: error: declaration of ‘typedef int ConstexprVector<T, N>::T’ shadows template parameter
prog.cpp:4:10: note: template parameter ‘T’ declared here
 template<class T,std::size_t N>
          ^~~~~
prog.cpp:12:28: error: ISO C++ forbids declaration of ‘ConstIterator’ with no type [-fpermissive]
  typedef typename T const* ConstIterator;
                            ^~~~~~~~~~~~~
prog.cpp:68:12: error: ‘Iterator’ does not name a type
  constexpr Iterator begin() {
            ^~~~~~~~
prog.cpp:72:12: error: ‘ConstIterator’ does not name a type
  constexpr ConstIterator begin() const {
            ^~~~~~~~~~~~~
prog.cpp:75:12: error: ‘Iterator’ does not name a type
  constexpr Iterator end() {
            ^~~~~~~~
prog.cpp:78:12: error: ‘ConstIterator’ does not name a type
  constexpr ConstIterator end() const {
            ^~~~~~~~~~~~~
prog.cpp: In function ‘constexpr uint64_t Calc2(const DType&)’:
prog.cpp:103:15: error: ‘begin’ was not declared in this scope
  for (auto& o:D) {
               ^
prog.cpp:103:15: note: suggested alternative:
In file included from /usr/include/c++/6/string:51:0,
                 from /usr/include/c++/6/stdexcept:39,
                 from /usr/include/c++/6/array:39,
                 from prog.cpp:1:
/usr/include/c++/6/bits/range_access.h:105:37: note:   ‘std::begin’
   template<typename _Tp> const _Tp* begin(const valarray<_Tp>&);
                                     ^~~~~
prog.cpp:103:15: error: ‘end’ was not declared in this scope
  for (auto& o:D) {
               ^
prog.cpp:103:15: note: suggested alternative:
In file included from /usr/include/c++/6/string:51:0,
                 from /usr/include/c++/6/stdexcept:39,
                 from /usr/include/c++/6/array:39,
                 from prog.cpp:1:
/usr/include/c++/6/bits/range_access.h:107:37: note:   ‘std::end’
   template<typename _Tp> const _Tp* end(const valarray<_Tp>&);
                                     ^~~
prog.cpp: In function ‘constexpr DType Add(const DType&, ConstexprVector<long unsigned int, 128ul>::ValueType)’:
prog.cpp:119:12: error: ‘const DType {aka const class ConstexprVector<long unsigned int, 128ul>}’ has no member named ‘begin’
  DType R(D.begin(), D.end());
            ^~~~~
prog.cpp:119:23: error: ‘const DType {aka const class ConstexprVector<long unsigned int, 128ul>}’ has no member named ‘end’
  DType R(D.begin(), D.end());
                       ^~~
prog.cpp: In function ‘int main()’:
prog.cpp:126:31: error: ‘constexpr ConstexprVector<T, N>::ConstexprVector(const std::initializer_list<_Tp>&) [with T = long unsigned int; long unsigned int N = 128ul]’ called in a constant expression
  constexpr DType D{ 1,2,3,4,5 };
                               ^
prog.cpp:14:21: note: ‘constexpr ConstexprVector<T, N>::ConstexprVector(const std::initializer_list<_Tp>&) [with T = long unsigned int; long unsigned int N = 128ul]’ is not usable as a constexpr function because:
  constexpr explicit ConstexprVector(const std::initializer_list<T>& L) {
                     ^~~~~~~~~~~~~~~
prog.cpp:14:21: error: member ‘ConstexprVector<long unsigned int, 128ul>::Iterator’ must be initialized by mem-initializer in ‘constexpr’ constructor
prog.cpp:11:22: note: declared here
  typedef typename T* Iterator;
                      ^~~~~~~~
prog.cpp:14:21: error: member ‘ConstexprVector<long unsigned int, 128ul>::ConstIterator’ must be initialized by mem-initializer in ‘constexpr’ constructor
  constexpr explicit ConstexprVector(const std::initializer_list<T>& L) {
                     ^~~~~~~~~~~~~~~
prog.cpp:12:28: note: declared here
  typedef typename T const* ConstIterator;
                            ^~~~~~~~~~~~~
prog.cpp:128:36: error: ‘constexpr uint64_t Calc2(const DType&)’ called in a constant expression
  constexpr std::uint64_t R2 = Calc2(D);
                               ~~~~~^~~
prog.cpp:129: confused by earlier errors, bailing out
stdout
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Standard output is empty
https://ideone.com/QBggO4
language:
C++14 (gcc 8.3)
created:
7 years ago
visibility:
public

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