算子一元重载功能

Operator unary overloading function

本文关键字：一元 重载 功能      更新时间：2023-10-16

我遇到了一元运算符重载的问题。因此，在下面显示的代码中，我基本上没有得到与我的学校相匹配的预期结果。有关更多信息，请参见下文。函数有一些限制，我不能添加任何参数，否则会给我一个编译错误。那么我该怎么办呢？如果您需要更多信息，请告诉我。谢谢！

    Point& Point::operator-() 
{
    x = -x;
    y = -y;
    return *this;
}

结果如下：

我的一元测试

******

pt1 = (3,4(

pt2 = -pt1

pt1 = (-3，-4(

pt2 = (-3，-4(

pt3 = (-3,4(

pt4 = - - -pt3

pt3 = (3，-4(

pt4 = (3，-4(

学校的一元考试

pt1 = (3， 4(

pt2 = -pt1

pt1 = (3， 4(//

pt2 = (-3， -4(

pt3 = (-3， 4(

pt4 = - - -pt3

pt3 = (-3， 4(//

pt4 = (3， -4(

驱动程序文件

  void UnaryTest(void)
{
cout << "n********** Unary test ********** " << endl;
Point pt1(3, 4);
cout << "pt1 = " << pt1 << endl;
Point pt2 = -pt1;
cout << "pt2 = -pt1" << endl;
cout << "pt1 = " << pt1 << endl;
cout << "pt2 = " << pt2 << endl;
cout << endl;
Point pt3(-3, 4);
cout << "pt3 = " << pt3 << endl;
Point pt4 = - - -pt3;
cout << "pt4 = - - -pt3" << endl;
cout << "pt3 = " << pt3 << endl;
cout << "pt4 = " << pt4 << endl;
}

列表.h 文件

  class Point
  {
   public:
  explicit Point(double x, double y); 
  Point();
   double getX() const;
   double getY() const;
   Point operator+(const Point& other)const ;
   Point& operator+(double value);

   Point operator*(double value) ;
   Point operator%(double angle);

   double operator-(const Point& other)const ;
   Point operator-(double value);
   Point operator^(const Point& other);
   Point& operator+=(double value);
   Point& operator+=(const Point& other) ;
   Point& operator++();
   Point operator++(int); 
   Point& operator--(); 
   Point operator--(int); 
   Point& operator-() ;

        // Overloaded operators (14 member functions)
   friend std::ostream &operator<<( std::ostream &output, const Point 
  &point );
    friend std::istream &operator>>( std::istream  &input, Point 
  &point );
    // Overloaded operators (2 friend functions)
 private:
  double x; // The x-coordinate of a Point
  double y; // The y-coordinate of a Point
    // Helper functions
  double DegreesToRadians(double degrees) const;
  double RadiansToDegrees(double radians) const;
};
 // Point& Add(const Point& other); // Overloaded operators (2 non-member, 
 non-friend functions)
    // Point& Multiply(const Point& other);
    Point operator+( double value, const Point& other );
    Point operator*( double value, const Point& other );

原型是：

Point operator-(double value);

但您的实现是：

Point& Point::operator-()

这是行不通的(注意参考和不同的参数！

此外，您不应就地修改此运算符的对象。相反，您应该拥有以下内容：

Point operator-() const;

然后：

Point Point::operator-() const
{
    return Point(-x, -y);
}
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