fork download
copy 
  1. #include <iostream>
  2. #include <type_traits>
  3.  
  4. using namespace std;
  5.  
  6. class CBase{
  7. public:
  8.     void basefunc(){
  9.         cout << "basefunc" << endl;
  10.     }
  11. };
  12.  
  13.  
  14. template<typename T,bool is_derived_from_base>
  15. class Hoge_impl; // 何も定義しない
  16.  
  17. // 特殊化
  18. template<typename T>
  19. class Hoge_impl<T,true>{
  20.     T t;
  21. public:
  22.     void func(){
  23.         t.basefunc();
  24.     }
  25. };
  26.  
  27. template<typename T>
  28. class Hoge : private Hoge_impl<T,std::is_base_of<CBase,T>::value>{
  29. public:
  30.     using Hoge_impl<T,std::is_base_of<CBase,T>::value>::func;
  31. };
  32.  
  33. class CDerived1 : public CBase{
  34. };
  35. class CDerived2 : public CBase{
  36. };
  37. class CNotDerived{
  38. };
  39.  
  40. int main()
  41. {
  42.     //これは通る。
  43.     Hoge<CDerived1> hoge1;
  44.     Hoge<CDerived2> hoge2;
  45.     //が、これは通らない。
  46.     //Hoge<CNotDerived> hoge3;
  47.     // Hoge<int> hoge4;
  48.  
  49.     hoge1.func();
  50.     hoge2.func();
  51.     // hoge3.func();
  52.     // hoge4.func();
  53.     return 0;
  54. }
Success #stdin #stdout 0s 3296KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
basefunc
basefunc
https://ideone.com/CENEJS
language:
C++14 (gcc 8.3)
created:
10 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!