insertion_emplacement.cpp 2.5 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109
  1. /* Copyright 2016-2017 Joaquin M Lopez Munoz.
  2. * Distributed under the Boost Software License, Version 1.0.
  3. * (See accompanying file LICENSE_1_0.txt or copy at
  4. * http://www.boost.org/LICENSE_1_0.txt)
  5. *
  6. * See http://www.boost.org/libs/poly_collection for library home page.
  7. */
  8. /* examples of insertion and emplacement */
  9. #include <algorithm>
  10. #include <array>
  11. #include <boost/poly_collection/base_collection.hpp>
  12. #include <random>
  13. #include "rolegame.hpp"
  14. int main()
  15. {
  16. boost::base_collection<sprite> c;
  17. // populate c
  18. std::mt19937 gen{92748}; // some arbitrary random seed
  19. std::discrete_distribution<> rnd{{1,1,1}};
  20. for(int i=0;i<8;++i){ // assign each type with 1/3 probability
  21. switch(rnd(gen)){
  22. case 0: c.insert(warrior{i});break;
  23. case 1: c.insert(juggernaut{i});break;
  24. case 2: c.insert(goblin{i});break;
  25. }
  26. }
  27. auto render=[](const boost::base_collection<sprite>& c){
  28. const char* comma="";
  29. for(const sprite& s:c){
  30. std::cout<<comma;
  31. s.render(std::cout);
  32. comma=",";
  33. }
  34. std::cout<<"\n";
  35. };
  36. render(c);
  37. //[insertion_emplacement_1]
  38. c.insert(c.begin(),juggernaut{8});
  39. //]
  40. render(c);
  41. //[insertion_emplacement_2]
  42. c.insert(c.begin(),goblin{9});
  43. //]
  44. render(c);
  45. //[insertion_emplacement_3]
  46. c.insert(c.begin<juggernaut>()+2,juggernaut{10});
  47. // ^^ remember local iterators are random access
  48. //]
  49. render(c);
  50. //[insertion_emplacement_4]
  51. //= c.insert(c.begin(typeid(warrior)),juggernaut{11}); // undefined behavior!!
  52. //]
  53. //[insertion_emplacement_5]
  54. boost::base_collection<sprite> c2;
  55. c2.insert(c.begin(),c.end()); // read below
  56. //<-
  57. render(c2);
  58. //->
  59. // add some more warriors
  60. std::array<warrior,3> aw={{11,12,13}};
  61. c2.insert(aw.begin(),aw.end());
  62. //<-
  63. render(c2);
  64. //->
  65. // add some goblins at the beginning of their segment
  66. std::array<goblin,3> ag={{14,15,16}};
  67. c2.insert(c2.begin<goblin>(),ag.begin(),ag.end());
  68. //<-
  69. render(c2);
  70. //->
  71. //]
  72. //[insertion_emplacement_6]
  73. //<-
  74. // same as line at beginning of previous snippet
  75. //->
  76. c2.insert(c.begin(),c.end());
  77. //]
  78. //[insertion_emplacement_7]
  79. //= c.emplace(11); // does not compile
  80. //]
  81. //[insertion_emplacement_8]
  82. c.emplace<goblin>(11); // now it works
  83. //]
  84. render(c);
  85. //[insertion_emplacement_9]
  86. c.emplace_hint<juggernaut>(c.begin(),12); // at the beginning if possible
  87. c.emplace_pos<goblin>(c.begin<goblin>()+2,13); // amidst the goblins
  88. c.emplace_pos<warrior>(c.begin(typeid(warrior)),14); // local_base_iterator
  89. //]
  90. render(c);
  91. }