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#ifndef POINT2D_H
#define POINT2D_H

#include "geometry_global.h"

//================================================================================================================================
// Точка в двумерном пространстве.
//================================================================================================================================
class GEOMETRY_EXPORT Point2D
{
public:
    Point2D();
    Point2D(double xc, double yc);

    double x() const;
    double y() const;
    void setX(double xc);
    void setY(double yc);

    friend inline bool operator==(const Point2D &p1, const Point2D &p2);
    friend inline bool operator!=(const Point2D &p1, const Point2D &p2);
    friend inline const Point2D operator-(const Point2D &point);

private:
    double m_x;
    double m_y;
};

#endif // POINT2D_H

#include "point2d.h"

//================================================================================================================================
//================================================================================================================================
inline Point2D::Point2D() : m_x(0.0), m_y(0.0){}
inline Point2D::Point2D(double xc, double yc) : m_x(xc), m_y(yc){}

//================================================================================================================================
//================================================================================================================================
inline double Point2D::x() const {return m_x;}
inline double Point2D::y() const {return m_y;}
inline void Point2D::setX(double xc){m_x = xc;}
inline void Point2D::setY(double yc){m_y = yc;}

//================================================================================================================================
//================================================================================================================================
inline bool operator==(const Point2D &p1, const Point2D &p2){return p1.m_x == p2.m_x && p1.m_y == p2.m_y;}
inline bool operator!=(const Point2D &p1, const Point2D &p2){return p1.m_x != p2.m_x || p1.m_y != p2.m_y;}
inline const Point2D operator-(const Point2D &point){return Point2D(-point.m_x, -point.m_y);}

#ifndef GEOMETRY_H
#define GEOMETRY_H

#include "point2d.h"
#include "geometry_global.h"

//================================================================================================================================
// Расстояние между точками A и B.
//================================================================================================================================
double GEOMETRY_EXPORT distance(const Point2D &A, const Point2D &B);

//================================================================================================================================
// Площадь треугольника ABC.
//================================================================================================================================
double GEOMETRY_EXPORT squareTriangle(const Point2D &A, const Point2D &B, const Point2D &C);

//================================================================================================================================
// Проверка, принадлежит ли точка Z треугольнику ABC.
//================================================================================================================================
bool GEOMETRY_EXPORT pointInsideTriangle(const Point2D &A, const Point2D &B, const Point2D &C, const Point2D &Z);

#endif // GEOMETRY_H

#include <math.h>
#include <float.h>
#include "geometry.h"

//================================================================================================================================
// Расстояние между точками A и B.
//================================================================================================================================
inline double GEOMETRY_EXPORT distance(const Point2D &A, const Point2D &B)
{
    return sqrt((A.x() - B.x())*(A.x() - B.x()) + (A.y() - B.y())*(A.y() - B.y()));
}

//================================================================================================================================
// Площадь треугольника ABC.
//================================================================================================================================
inline double GEOMETRY_EXPORT squareTriangle(const Point2D &A, const Point2D &B, const Point2D &C)
{
    return qAbs((B.x() - A.x())*(C.y() - A.y()) - (C.x() - A.x())*(B.y() - A.y()))/2.;
}

//================================================================================================================================
// Проверка, принадлежит ли точка Z треугольнику ABC.
//================================================================================================================================
bool GEOMETRY_EXPORT pointInsideTriangle(const Point2D &A, const Point2D &B, const Point2D &C, const Point2D &Z)
{
    double s = squareTriangle(A, B, C);
    double s1 = squareTriangle(Z, B, C);
    double s2 = squareTriangle(A, Z, C);
    double s3 = squareTriangle(A, B, Z);

    if(qAbs(s - s1 - s2 - s3) < DBL_EPSILON)
        return true;
    else
        return false;
}

release/geometry.o:geometry.cpp:(.text$_Z14squareTriangleRK7Point2DS1_S1_[squareTriangle(Point2D const&, Point2D const&, Point2D const&)]+0x16): undefined reference to `Point2D::x() const' 
release/geometry.o:geometry.cpp:(.text$_Z14squareTriangleRK7Point2DS1_S1_[squareTriangle(Point2D const&, Point2D const&, Point2D const&)]+0x21): undefined reference to `Point2D::x() const' 
release/geometry.o:geometry.cpp:(.text$_Z14squareTriangleRK7Point2DS1_S1_[squareTriangle(Point2D const&, Point2D const&, Point2D const&)]+0x2c): undefined reference to `Point2D::y() const' 
release/geometry.o:geometry.cpp:(.text$_Z14squareTriangleRK7Point2DS1_S1_[squareTriangle(Point2D const&, Point2D const&, Point2D const&)]+0x37): undefined reference to `Point2D::y() const' 
release/geometry.o:geometry.cpp:(.text$_Z14squareTriangleRK7Point2DS1_S1_[squareTriangle(Point2D const&, Point2D const&, Point2D const&)]+0x42): undefined reference to `Point2D::x() const' 
release/geometry.o:geometry.cpp:(.text$_Z14squareTriangleRK7Point2DS1_S1_[squareTriangle(Point2D const&, Point2D const&, Point2D const&)]+0x4d): undefined reference to `Point2D::x() const' 
release/geometry.o:geometry.cpp:(.text$_Z14squareTriangleRK7Point2DS1_S1_[squareTriangle(Point2D const&, Point2D const&, Point2D const&)]+0x58): undefined reference to `Point2D::y() const' 
release/geometry.o:geometry.cpp:(.text$_Z14squareTriangleRK7Point2DS1_S1_[squareTriangle(Point2D const&, Point2D const&, Point2D const&)]+0x63): undefined reference to `Point2D::y() const' 
collect2: ld returned 1 exit status