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  1. #include <set>
  2. #include <iostream>
  3. #include <iterator>
  4. #include <string>
  5.  
  6. class Student { 
  7. 	std::string name;
  8. 	std::string surname;
  9. 	int id;
  10. 	static int next_id;
  11. public:
  12. 	bool operator<(Student const &other) const { 
  13. 		return id < other.id;
  14. 	}
  15.  
  16. 	std::string getName() const { return name; }
  17. 	std::string getSurName() const { return surname; }
  18.  
  19. 	Student(std::string const &n, std::string const &sn) : name(n), surname(sn), id(next_id++) {}
  20.  
  21. 	friend std::ostream &operator<<(std::ostream &os, Student const &s) {
  22. 		return os << s.id << "\t" << s.getName() << "\t" << s.getSurName();
  23. 	}
  24. };
  25.  
  26. int Student::next_id;
  27.  
  28. struct by_given_name {
  29.     bool operator()(Student const &a, Student const &b) const { 
  30.         if (a.getName() < b.getName())
  31.             return true;
  32.         if (b.getName() < a.getName())
  33.             return false;
  34.         return a.getSurName() < b.getSurName();
  35.     }
  36. };
  37.  
  38.  
  39. std::set<Student, by_given_name> xform(std::set<Student> const &in) { 
  40.     return std::set<Student, by_given_name>{in.begin(), in.end()};
  41. }
  42.  
  43. int main() {
  44. 	std::set<Student> students {
  45. 		{"Albert", "Einstein"},
  46. 		{"Marie", "Curie"},
  47. 		{"Louis", "Pasteur"}
  48. 	};
  49.  
  50. 	auto reordered = xform(students);
  51.  
  52. 	std::cout << "Original order:\n";
  53. 	std::copy(students.begin(), students.end(), 
  54. 			std::ostream_iterator<Student>(std::cout, "\n"));
  55.  
  56. 	std::cout << "\nOrdered by name:\n";
  57. 	std::copy(reordered.begin(), reordered.end(),
  58. 		std::ostream_iterator<Student>(std::cout, "\n"));
  59. }
  60.  
Success #stdin #stdout 0s 3440KB
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stdin
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Standard input is empty
stdout
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Original order:
0	Albert	Einstein
1	Marie	Curie
2	Louis	Pasteur

Ordered by name:
0	Albert	Einstein
2	Louis	Pasteur
1	Marie	Curie
https://ideone.com/tPIzPT
language:
C++14 (gcc 8.3)
created:
11 years ago
visibility:
public

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