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  1. #include <iostream>
  2. #include <functional>
  3. #include <string>
  4. #include <random>
  5. using namespace std;
  6.  
  7.  
  8. template<typename T>
  9. class Attemptor{
  10. public:
  11.     struct Actions{ 
  12.         function<T()> in;
  13.         function<bool(T)> onCheck; 
  14.         function<void(T)> onSuccess;
  15.         function<void(T)> onPartialFailure;
  16.         function<void(T)> onTotalFailure;
  17.         function<void()> onNoMoreAttemptsLeft;
  18.     };
  19.  
  20.     Attemptor(Actions actions, size_t maxFailures)
  21.         : _actions(actions), _maxFailures(maxFailures), _failures(0){}
  22.  
  23.     bool canAttempt() const{
  24.         return !_success && _maxFailures > _failures;
  25.     }
  26.  
  27.     bool isDone() const{
  28.     	return _done;
  29.     }
  30.  
  31. 	bool success() const{
  32. 		return _success;
  33. 	}
  34.  
  35.     bool attempt(){
  36.         if(!canAttempt()){
  37.             _actions.onNoMoreAttemptsLeft();
  38.             return false;
  39.         };
  40.         T in_result = _actions.in();
  41.         if(_actions.onCheck(in_result)){
  42.             _actions.onSuccess(in_result);
  43.             return finishWithSuccessEq(true);
  44.         }
  45.         _failures += 1;
  46.         if(canAttempt()) _actions.onPartialFailure(in_result);
  47.         else {
  48.         	_actions.onTotalFailure(in_result);
  49.         	return finishWithSuccessEq(false);
  50.         }
  51.  
  52.     }
  53. private:
  54. 	bool finishWithSuccessEq(bool val){
  55. 		_done = true;
  56. 		return _success = val;
  57. 	}
  58. 	bool _done = false;
  59. 	bool _success = false;
  60.     const Actions _actions;
  61.     const size_t _maxFailures;
  62.     size_t _failures;
  63. };
  64.  
  65. template<typename T>
  66. auto read(istream &in = cin){
  67. 	T var;
  68. 	in >> var;
  69. 	return var;
  70. }
  71.  
  72. int main() {
  73. 	size_t min = 1, max = 100, attempts = 10;
  74.  
  75. 	default_random_engine gen(0xCafeBabe);
  76. 	uniform_int_distribution<> dist(min, max);
  77.  
  78. 	auto number = dist(gen);
  79.  
  80. 	using attemptor_type = Attemptor<int>;
  81. 	using actions_type = typename attemptor_type::Actions;
  82.  
  83. 	auto attemptor = attemptor_type(
  84. 		actions_type{
  85. 			[]{ return read<int>(); },
  86. 			[number](int in){ return in == number; },
  87. 			[](int res){cout << "Success with " << res << "!" << endl;},
  88.             [number](int res){cout << (res<number? "<":">") << endl;},
  89.             [](int res){cout << "Total failure with " << res << "!" << endl;},
  90.             []{cout << "No more attempts left!" << endl;}
  91. 		}, attempts
  92. 	);
  93.  
  94. 	while(!attemptor.attempt());
  95. 	return 0;
  96. }
Success #stdin #stdout 0s 3284KB
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<
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<
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Success with 20!
https://ideone.com/sl7f4O
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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