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  1. #include <functional>
  2. #include <iostream>
  3. #include <sstream>
  4. #include <iomanip>
  5. #include <string>
  6. #include <random>
  7. #include <map>
  8. using namespace std;
  9.  
  10. class PersonalIdentificationNumber{
  11. public:
  12. 	static constexpr unsigned LENGTH = 4;
  13.  
  14. 	explicit PersonalIdentificationNumber(unsigned number): _number(number){
  15. 		cut_if_necessary(_number);
  16. 	}
  17.  
  18. 	operator unsigned() const{ return _number; }
  19.  
  20. 	string formatted() const{
  21. 		ostringstream ss;
  22. 	 	ss << setw(LENGTH) << setfill('0') << _number;
  23. 		return ss.str();
  24. 	}
  25. private:
  26. 	void cut_if_necessary(unsigned &number) const{
  27. 		while(number >= 10000)
  28. 			number /= 10;
  29. 	}
  30. 	unsigned _number;
  31. };
  32.  
  33. using PID = PersonalIdentificationNumber;
  34.  
  35. bool operator==(const PID &lhs, const PID &rhs){
  36. 	return (unsigned)lhs == (unsigned)rhs;
  37. }
  38.  
  39. template<typename T>
  40. class LoginAttemptor{
  41. public:
  42. 	struct Actions{ 
  43. 		function<T()> in;
  44. 		function<bool(T)> onCheck; 
  45. 		function<void(T)> onSuccess;
  46. 		function<void(T)> onPartialFailure;
  47. 		function<void(T)> onTotalFailure;
  48. 		function<void()> onNoMoreAttemptsLeft;
  49. 	};
  50.  
  51. 	LoginAttemptor(Actions actions, size_t maxFailures)
  52. 		: _actions(actions), _maxFailures(maxFailures), _failures(0){}
  53.  
  54. 	bool canAttempt() const{
  55. 		return _maxFailures > _failures;
  56. 	}
  57.  
  58. 	bool attempt(){
  59. 		if(!canAttempt()){
  60. 			_actions.onNoMoreAttemptsLeft();
  61. 			return false;
  62. 		};
  63. 		T in_result = _actions.in();
  64. 		if(_actions.onCheck(in_result)){
  65. 			_actions.onSuccess(in_result);
  66. 			return true;
  67. 		}
  68. 		_failures += 1;
  69. 		if(canAttempt()) _actions.onPartialFailure(in_result);
  70. 		else _actions.onTotalFailure(in_result);
  71. 	}
  72. private:
  73. 	const Actions _actions;
  74. 	const size_t _maxFailures;
  75. 	size_t _failures;
  76. };
  77.  
  78. int main(){
  79. 	const size_t maxNumberOfLoginAttempts = 3;
  80. 	PersonalIdentificationNumber a(1), b(10000);
  81. 	cout << a.formatted() << " " << b.formatted() << endl;
  82.  
  83. 	auto loginAttemptor = LoginAttemptor<PID>({
  84. 			[]{unsigned in; cin >> in; return PID(in);},
  85. 			[](PID r){return r == PID(133);},
  86. 			[](PID r){cout << "Success with " << r.formatted() << "!" << endl;},
  87. 			[](PID r){cout << "Partial failure with " << r.formatted() << "." << endl;},
  88. 			[](PID r){cout << "Total failure with " << r.formatted() << "!" << endl;},
  89. 			[]{cout << "No more attempts left!" << endl;}
  90. 		}, maxNumberOfLoginAttempts
  91. 	), copy = loginAttemptor;
  92.  
  93. 	for(size_t i = 0; i <= maxNumberOfLoginAttempts; ++i)
  94. 		loginAttemptor.attempt();
  95.  
  96. 	while(!copy.attempt());
  97. 	return 0;
  98. }
Success #stdin #stdout 0s 3444KB
comments (?)
stdin
copy 
1 2 3 4 133
stdout
copy 
0001 1000
Partial failure with 0001.
Partial failure with 0002.
Total failure with 0003!
No more attempts left!
Partial failure with 0004.
Success with 0133!
https://ideone.com/W28k7H
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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