C++ 단항 연산자 오버로딩 (Unary Operator Overloading)

단항 연산자 오버로딩 (Unary Operator Overloading)

• -, ! 오버로딩

  #include <iostream>
  
  class Cents
  {
    int    cents_;
  
  public:
    Cents(int cents = 0) { cents_ = cents; }
  
    Cents operator - () const
    {
      return Cents(-cents_);
    }
  
    bool operator ! () const
    {
      return (cents_ == 0) ? true : false;
    }
  
    friend std::ostream& operator << (std::ostream& out, const Cents& cents)
    {
      out << cents.cents_;
      return (out);
    }
  };
  
  int        main()
  {
    using namespace std;
  
    Cents    c1{ 6 };
    Cents    c2{ 0 };
  
    cout << -c1 << ' ' << -c2 << endl;
    cout << std::boolalpha;
    cout << !c1 << ' ' << !c2 << endl;
  }
  
  /* stdout
  -6 0
  false true
  */