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  1. #include <iostream>
  2. #include <iomanip>
  3.  
  4. class A {
  5. public:
  6.     A() { std::cout << "ctor A" << std::hex << this << std::endl ; }
  7.     A(const A&) { std::cout << "cctor A" << std::hex << this << std::endl ; }
  8.     ~A() { std::cout << "dtor A" << std::hex << this << std::endl ; }
  9. } ;
  10.  
  11. class B {
  12.   public:
  13.   A f1() {
  14.     std::cout << "before f2()" << std::endl ;
  15.     const A& a = f2();
  16.     std::cout << "after f2()" << std::endl ;
  17.     /*Какие-то вычисления. Просто "return f2();", чтобы без лишних копирований, сделать не удасться.*/
  18.     return a;
  19.   }
  20.   private:
  21.   virtual const A& f2() {
  22.     std::cout << "f2() create object a" << std::endl ;
  23.     A a;
  24.     std::cout << "f2() return reference for object a" << std::endl ;
  25.     return a;
  26.   }
  27. } ;
  28.  
  29.  
  30. int main()
  31. {
  32.     B b ;
  33.     b.f1() ;
  34. }
  35.  
Success #stdin #stdout 0s 3300KB
comments (?)
stdin
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Standard input is empty
stdout
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before f2()
f2() create object a
ctor A0xbfbea1ff
f2() return reference for object a
dtor A0xbfbea1ff
after f2()
cctor A0xbfbea1fe
dtor A0xbfbea1fe
https://ideone.com/fB2mX9
language:
C++14 (gcc 8.3)
created:
8 years ago
visibility:
public

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