fork download
copy 
  1. #include <iostream>
  2.  
  3. template <typename T>
  4. struct valdef
  5. {
  6. 	typedef T value;
  7. };
  8.  
  9. template <char... C>
  10. struct string
  11. {
  12. 	static char const c_str[];
  13. };
  14.  
  15. template <char... C>
  16. char const string<C...>::c_str[] = { C..., 0 };
  17.  
  18. template <typename, typename>
  19. struct append;
  20.  
  21. template <char... C, char... D>
  22. struct append<string<C...>, string<D...>>
  23. 	: valdef<string<C..., D...>>
  24. {};
  25.  
  26. template <char C, unsigned N>
  27. struct make_string_n
  28. 	: valdef
  29. 	<
  30. 		typename append
  31. 		<
  32. 			typename make_string_n<C, N - 1>::value,
  33. 			string<C>
  34. 		>::value
  35. 	>
  36. {};
  37.  
  38. template <char C>
  39. struct make_string_n<C, 0>
  40. 	: valdef<string<>>
  41. {};
  42.  
  43. template <char C, unsigned Chars, char F, unsigned Fills>
  44. struct make_rhombus_line
  45. 	: valdef
  46. 	<
  47. 		typename append
  48. 		<
  49. 			typename append
  50. 			<
  51. 				typename make_string_n<F, Fills>::value,
  52. 				typename make_string_n<C, Chars>::value
  53. 			>::value,
  54. 			string<'\n'>
  55. 		>::value
  56. 	>
  57. {};
  58.  
  59. template <char C, unsigned Chars, char F, unsigned Fills>
  60. struct rhombus
  61. 	: valdef
  62. 	<
  63. 		typename append
  64. 		<
  65. 			typename make_rhombus_line<C, Chars, F, Fills>::value,
  66. 			typename append
  67. 			<
  68. 				typename rhombus<C + 1, Chars + 2, F, Fills - 1>::value,
  69. 				typename make_rhombus_line<C, Chars, F, Fills>::value
  70. 			>::value
  71. 		>::value
  72. 	>
  73. {};
  74.  
  75. template <char C, unsigned Chars, char F>
  76. struct rhombus<C, Chars, F, 0>
  77. 	: valdef<typename make_rhombus_line<C, Chars, F, 0>::value>
  78. {};
  79.  
  80. template <char C, char F>
  81. struct make_rhombus
  82. 	: valdef<typename rhombus<'A', 1, F, C - 'A'>::value>
  83. {};
  84.  
  85. int main()
  86. {
  87. 	std::cout << make_rhombus<'D', ' '>::value::c_str;
  88. }
Success #stdin #stdout 0s 2828KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
   A
  BBB
 CCCCC
DDDDDDD
 CCCCC
  BBB
   A
https://ideone.com/fufGJ
language:
C++14 (gcc 8.3)
created:
14 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!