fork download 
  1. #include <set>
  2. #include <iostream>
  3. using namespace std;
  4.  
  5. template<class T> 
  6. class A 
  7. {   
  8.     public:
  9.         A(T a = T(), T b = T()): m_a(a), m_b(b) {}
  10.  
  11.         bool operator<(const A& rhs) const
  12.         {
  13.             return ((m_a < rhs.m_a) ||
  14.                     ((m_a == rhs.m_a) && (m_b < rhs.m_b))
  15.                    );
  16.             /* alterrnatively:
  17.             return std::tie(m_a, m_b) < std::tie(rhs.m_a, rhs.m_b);
  18.             */
  19.         }
  20.  
  21.         friend ostream& operator<<(ostream &out, const A& value)
  22.         {
  23.             return out << value.m_a << ' ' << value.m_b;
  24.         }
  25.  
  26.     private:
  27.         T m_a;
  28.         T m_b;   
  29. };  
  30.  
  31. int main()   
  32. {
  33.     A<int> abc(2,3);
  34.     A<int> def(1,5);
  35.  
  36.     set<A<int>> P2D;
  37.     P2D.insert(abc);
  38.     P2D.insert(def);
  39.  
  40. 	for(const auto &elem : P2D) {
  41. 		cout << elem << endl;
  42. 	}
  43.  
  44.     return 0;   
  45. }
Success #stdin #stdout 0.01s 5516KB
comments (?)
stdin 
Standard input is empty
stdout 
1 5
2 3
https://ideone.com/JhssAu
language:
C++ 4.3.2 (gcc-4.3.2)
created:
4 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!