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  1. ///////////////////////////////////////////////////////////////////////////////
  2. // ClassTemplate.hpp
  3.  
  4. //#pragma once
  5.  
  6. #include <iostream>
  7.  
  8. template <typename T>
  9. class ClassTemplate
  10. {
  11. public:
  12.    ClassTemplate()
  13.    {
  14.       std::cout << "ClassTemplate constructor" << std::endl;
  15.    }
  16.  
  17.    void Test()
  18.    {
  19.       std::cout << "ClassTemplate Test" << std::endl;
  20.    }
  21. };
  22.  
  23. ///////////////////////////////////////////////////////////////////////////////
  24. // a.hpp
  25.  
  26. //#pragma once
  27.  
  28. // declare that somewhere this will be defined
  29. extern ClassTemplate<int> obj; // NOT constructed here!
  30.  
  31. class A
  32. {
  33.    public:
  34.       A()
  35.       {
  36.          // use it
  37.          obj.Test();
  38.       }
  39. };
  40.  
  41. ///////////////////////////////////////////////////////////////////////////////
  42. // a.cpp
  43.  
  44. //#include "ClassTemplate.hpp"
  45. //#include "a.hpp"
  46.  
  47. // create object (point of instantiation)
  48. ClassTemplate<int> obj;
  49.  
  50. int main( int argc, char ** argv )
  51. {
  52.    A a; // construct A, which uses obj
  53. }
  54.  
  55. ///////////////////////////////////////////////////////////////////////////////
Success #stdin #stdout 0s 3456KB
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ClassTemplate constructor
ClassTemplate Test
https://ideone.com/Ijnhul
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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