CGAL 4.14 - 2D Periodic Triangulations
Periodic_2Offset_2 Concept Reference

## Definition

The concept Periodic_2Offset_2 describes a two-/dimensional integer vector with some specialized access functions and operations.

Has Models:
CGAL::Periodic_2_offset_2
See also
Periodic_2TriangulationTraits_2
Periodic_2DelaunayTriangulationTraits_2

## Related Functions

(Note that these are not member functions.)

istream & operator>> (istream &is, Periodic_2Offset_2 &off)
Inputs an offset from is.

ostream & operator<< (ostream &os, Periodic_2Offset_2 &off) const
Outputs an offset from os.

## Creation

Periodic_2Offset_2 ()
Default constructor.

Periodic_2Offset_2 (int x, int y)
Constructs the offset (x,y).

## Operations

Periodic_2Offset_2 operator+ (const Periodic_2Offset_2 &o) const
Return the vector sum of this and o.

Periodic_2Offset_2 operator- (const Periodic_2Offset_2 &o) const
Return the vector difference of this and o.

Periodic_2Offset_2 operator- () const
Return the negative vector of this.

void operator+= (const Periodic_2Offset_2 &o) const
Add o to this using vector addition.

void operator-= (const Periodic_2Offset_2 &o) const
Subtract o from this using vector subtraction.

bool operator== (const Periodic_2Offset_2 &o) const
Return true if o and this represent the same vector.

bool operator!= (const Periodic_2Offset_2 &o) const
Return true if o and this do not represent the same vector.

bool operator< (const Periodic_2Offset_2 &o) const
Compare this and o lexicographically.

## Access Functions

int operator[] (int i)
Return the $$i$$-th entry of this. More...

int x () const
Return the $$x$$-entry of this.

int y () const
Return the $$y$$-entry of this.

bool is_null () const
Returns true if this is equal to (0,0).

bool is_zero () const
Returns true if this is equal to (0,0).

## ◆ operator[]()

 int Periodic_2Offset_2::operator[] ( int i )

Return the $$i$$-th entry of this.

Precondition
$$i\in\{0,1\}$$