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  1. #include <cstdio>
  2.  
  3. template<typename T>
  4. class Test {
  5. private:
  6.     T value_;
  7.  
  8. public:
  9.     mutable bool has_copies;
  10.  
  11.     Test(const T& value) : value_(value), has_copies(false) {}
  12.  
  13.     template<typename Related> // remove template here to fix behavior
  14.     Test(const Test<Related>& t) {
  15.         printf("In copy constructor\n"); fflush(stdout);
  16.         value_ = t.value_;
  17.         has_copies = true;
  18.         t.has_copies = true;
  19.     }
  20. };
  21.  
  22. int main() {
  23.     Test<int> t1(42);
  24.     printf("Before constructor\n");
  25.     Test<int> t2(t1);
  26.     printf("After constructor:\n");
  27.     printf("    t1 thinks it %s copies\n", t1.has_copies ? "has" : "doesn't have");
  28.     printf("    t2 thinks it %s copies\n", t2.has_copies ? "has" : "doesn't have");
  29. }
Success #stdin #stdout 0s 3468KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
Before constructor
After constructor:
    t1 thinks it doesn't have copies
    t2 thinks it doesn't have copies
https://ideone.com/12e1Dr
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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