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  1. 	#include <algorithm>
  2. 	#include <functional>
  3. 	#include <iostream>
  4. 	#include <string>
  5.  
  6. 	struct TeamStats {
  7. 		std::string name;
  8. 		float yards_per_game;
  9. 		int total_points;
  10. 	};
  11.  
  12. 	using QuickSortPred = std::function<bool(const TeamStats&, const TeamStats&)>;
  13.  
  14. 	template<typename I>
  15. 	void quickSort(I begin, I end, QuickSortPred predicate)
  16. 	{
  17. 		/// NOTE: This is NOT a complete quicksort, it's just to demonstrate
  18. 		/// the usage of predicate.
  19.  
  20. 		std::sort(begin, end, predicate);	
  21. 	}
  22.  
  23. 	int main() {
  24. 		std::vector<TeamStats> arr {
  25. 			{ "Red",   100, 30, },
  26. 			{ "Blue",  150, 10, },
  27. 			{ "Green", 200, 20, },
  28. 		};
  29.  
  30. 		// approach one, store the lambda before hand
  31. 		auto sortByYards = [](const TeamStats& lhs, const TeamStats& rhs) -> bool {
  32. 			return lhs.yards_per_game < rhs.yards_per_game;
  33. 		};
  34. 		quickSort(arr.begin(), arr.end(), sortByYards);
  35. 		std::cout << "By yards:\n";
  36. 		for (auto& it : arr) {
  37. 			std::cout << it.yards_per_game << " " << it.name << "\n";
  38. 		}
  39.  
  40. 		// approach two, write the lambda inline.
  41. 		quickSort(arr.begin(), arr.end(), [](const TeamStats& lhs, const TeamStats& rhs) -> bool {
  42. 			return lhs.total_points < rhs.total_points;
  43. 		});
  44. 		std::cout << "By points:\n";
  45. 		for (auto& it : arr) {
  46. 			std::cout << it.total_points << " " << it.name << "\n";
  47. 		}
  48.  
  49. 		return 0;
  50. 	}
Success #stdin #stdout 0s 3468KB
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Standard input is empty
stdout
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By yards:
100 Red
150 Blue
200 Green
By points:
10 Blue
20 Green
30 Red
https://ideone.com/N35RRn
language:
C++14 (gcc 8.3)
created:
9 years ago
visibility:
public

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