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  1. #include <algorithm>
  2. #include <functional>
  3. #include <iostream>
  4. #include <map>
  5. #include <string>
  6.  
  7. using namespace std;
  8.  
  9. int main() {
  10. 	const auto cmp1 = [ordering = { "dog"s, "cat"s, "mouse"s, "elephant"s }](const string& lhs, const string& rhs) { return find(cbegin(ordering), cend(ordering), lhs) < find(cbegin(ordering), cend(ordering), rhs); };
  11. 	const auto cmp2 = [ordering = { "dog", "cat", "mouse", "elephant" }](const string& lhs, const string& rhs) { return find(cbegin(ordering), cend(ordering), lhs) < find(cbegin(ordering), cend(ordering), rhs); };
  12.  
  13. 	map<string, int, function<bool(const string&, const string&)>> myMap1(cmp1);
  14.  
  15. 	myMap1["cat"s] = 1;
  16. 	myMap1["dog"s] = 2;
  17. 	myMap1["elephant"s] = 3;
  18. 	myMap1["mouse"s] = 4;
  19. 	myMap1["rhino"s] = 5;
  20.  
  21.     cout << "Wrong:\n";
  22.  
  23. 	for (auto& i : myMap1) {
  24. 		cout << '\t' << i.first << ' ' << i.second << endl;
  25. 	}
  26.  
  27. 	map<string, int, function<bool(const string&, const string&)>> myMap2(cmp2);
  28.  
  29. 	myMap2["cat"s] = 1;
  30. 	myMap2["dog"s] = 2;
  31. 	myMap2["elephant"s] = 3;
  32. 	myMap2["mouse"s] = 4;
  33. 	myMap2["rhino"s] = 5;
  34.  
  35. 	cout << "Right:\n";
  36.  
  37. 	for (auto& i : myMap2) {
  38. 		cout << '\t' << i.first << ' ' << i.second << endl;
  39. 	}	
  40. }
Success #stdin #stdout 0s 3420KB
comments (?)
stdin
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Standard input is empty
stdout
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Wrong:
	cat 1
	dog 2
	mouse 4
	elephant 5
Right:
	dog 2
	cat 1
	mouse 4
	elephant 3
	rhino 5
https://ideone.com/4dRKmJ
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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