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  1.     #include <iostream>
  2.  
  3.     template<class Derived>
  4.     class Singleton {
  5.     public:
  6.         static Derived& instance() {
  7.             static Derived theInstance;
  8.             return theInstance;
  9.         }
  10.  
  11.     protected:
  12.         Singleton() {}
  13.  
  14.     private:
  15.         Singleton(const Singleton<Derived>&);
  16.         Singleton<Derived>& operator=(const Singleton<Derived>&);
  17.     };
  18.  
  19.     class ASingleton : public Singleton<ASingleton> {
  20.     public:
  21. 	    void foo() { std::cout << "foo() called ..." << std::endl; }
  22.     };
  23.  
  24.     int main() {
  25. 	    ASingleton& a = ASingleton::instance();
  26. 	    a.foo();
  27. 	    return 0;
  28.     }
Success #stdin #stdout 0s 3296KB
comments (?)
stdin 
Standard input is empty
stdout 
foo() called ...
https://ideone.com/KdvW5M
language:
C++14 (gcc 8.3)
created:
10 years ago
visibility:
public

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