Design Patterns : Elements of Reusable Object-Oriented Software

Design Patterns: Elements of Reusable Object-Oriented Software 
414 
Point& operator-=(const Point&); 
Point& operator*=(const Point&); 
Point& operator/=(const Point&); 
Point operator-();
friend bool operator==(const Point&, const Point&); 
friend bool operator!=(const Point&, const Point&); 
friend ostream& operator<<(ostream&, const Point&); 
friend istream& operator>>(istream&, Point&); 
}; 
The static member Zero represents Point(0, 0). 
Rect 
Rect represents an axis-aligned rectangle. ARect is defined by an origin point 
and an extent (thatis, width and height). The Rect operations areself-explanatory. 
class Rect { 
public: 
static const Rect Zero; 
Rect(Coord x, Coord y, Coord w, Coord h); 
Rect(const Point& origin, const Point& extent); 
Coord Width() const; void Width(Coord); 
Coord Height() const; void Height(Coord); 
Coord Left() const; void Left(Coord); 
Coord Bottom() const; void Bottom(Coord); 
Point& Origin() const; void Origin(const Point&); 
Point& Extent() const; void Extent(const Point&); 
void MoveTo(const Point&); 
void MoveBy(const Point&); 
bool IsEmpty() const; 
bool Contains(const Point&) const; 
}; 
The static member Zero is equivalent to the rectangle 

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Design Patterns: Elements of Reusable Object-Oriented Software 
415 
Rect(Point(0, 0), Point(0, 0)); 

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Design Patterns: Elements of Reusable Object-Oriented Software 
416 
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A Pattern Language
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