unordered_set::find

#include <unordered_set>
#include <iostream>
#include <algorithm>
#include <functional>
                                                                                                    
using std::unordered_set,
    std::hash,
    std::size_t,
    std::cerr;
                            
class Temp{
    public:
        int a, b;
        Temp(int i, int j):a(i), b(j){}
};
            
bool operator==(const Temp& l, const Temp& r)
{
    return l.a == r.a && l.b == r.b;
}
            
template<>
struct std::hash<Temp>
{
    size_t operator()(const Temp& temp) const noexcept
    {
        size_t h1 = hash<int>{}(temp.a);
        size_t h2 = hash<int>{}(temp.b);
        return h1 ^ (h2 << 1); // or use boost::hash_combine
    }
};
            
typedef unordered_set<Temp> my_unordered_set;
            
int main(){
                
    my_unordered_set a = {Temp(1,2), Temp(3,5)};
    my_unordered_set::iterator i = a.find(Temp(3,5));
    cerr << "i->a:" << i->a << " i->b: " << i->b << "\n";            
            
    return 0;
}