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  1. #include <iostream>
  2. #include <set>
  3. #include <cmath>
  4. #include <vector>
  5. #include <algorithm>
  6. #include <typeinfo>
  7. #include <map>
  8.  
  9. using namespace std;
  10.  
  11. template<typename... T>
  12. struct collection_traits { using template_type = void; };
  13.  
  14. template<template<typename...> class C, typename... Args>
  15. struct collection_traits<C<Args...> > {
  16.   template<typename... Subst>
  17.   using template_type = C<Subst...>;
  18. };
  19.  
  20.  
  21. template<typename a, typename b, typename c>
  22. struct A {
  23.   using a1 = a;
  24.   using b1 = b;
  25.   using c1 = c;
  26. };
  27.  
  28. int main(int argc, char *argv[]) {
  29.   collection_traits<vector<int>>::template_type<double> t;
  30.   collection_traits<map<int, int>>::template_type<string, string> t2;
  31.   collection_traits<set<int>>::template_type<double> t3;
  32.   collection_traits<A<int, int, int>>::template_type<string, string, string> t4;
  33.  
  34.   cout << typeid(t).name() << endl;
  35.   cout << typeid(t2).name() << endl;
  36.   cout << typeid(t3).name() << endl;
  37.   cout << typeid(t4).name() << endl;
  38.  
  39.   t.push_back(123.5);
  40.   t2["ASD"] = "QWE";
  41.   cout << t.front() << endl;
  42.  
  43.   for (auto e : t2)
  44.     cout << e.first << " " << e.second << endl;
  45.  
  46. }
  47.  
  48.  
  49.  
Success #stdin #stdout 0s 3416KB
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stdin
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Standard input is empty
stdout
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St6vectorIdSaIdEE
St3mapISsSsSt4lessISsESaISt4pairIKSsSsEEE
St3setIdSt4lessIdESaIdEE
1AISsSsSsE
123.5
ASD QWE
https://ideone.com/lbS2W3
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
secret

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