自学教程：C++ y函数代码示例

 /**  * Like rotate(), but returns a new point instead of changing *this  */ Point rotated(float angle) const {     float newX = x() * cos(angle) - y() * sin(angle);     float newY = y() * cos(angle) + x() * sin(angle);     return Point(newX, newY); }

bool isBoxIntersectingTriangle(const Box_f & box, const Triangle_f & triangle) {	/*    use separating axis theorem to test overlap between triangle and box */	/*    need to test for overlap in these directions: */	/*    1) the {x,y,z}-directions (actually, since we use the AABB of the triangle */	/*       we do not even need to test these) */	/*    2) normal of the triangle */	/*    3) crossproduct(edge from tri, {x,y,z}-directin) */	/*       this gives 3x3=9 more tests */	Vec3 boxcenter = box.getCenter();	Vec3 boxhalfsize(0.5f * box.getExtentX(), 0.5f * box.getExtentY(), 0.5f * box.getExtentZ());	/* This is the fastest branch on Sun */	/* move everything so that the boxcenter is in (0,0,0) */	const auto v0 = triangle.getVertexA() - boxcenter;	const auto v1 = triangle.getVertexB() - boxcenter;	const auto v2 = triangle.getVertexC() - boxcenter;	/* compute triangle edges */	const auto e0 = triangle.getEdgeAB();	const auto e1 = triangle.getEdgeBC();	const auto e2 = triangle.getEdgeCA();	/* Bullet 3:  */	/*  test the 9 tests first (this was faster) */	float p0, p1, p2, rad, pMin, pMax;	Vec3 fe = e0.getAbs();	p0 = e0.z() * v0.y() - e0.y() * v0.z();	p2 = e0.z() * v2.y() - e0.y() * v2.z();	if (p0 < p2) {		pMin = p0;		pMax = p2;	} else {		pMin = p2;		pMax = p0;	}	rad = fe.z() * boxhalfsize.y() + fe.y() * boxhalfsize.z();	if (pMin > rad || pMax < -rad)		return 0;	p0 = -e0.z() * v0.x() + e0.x() * v0.z();	p2 = -e0.z() * v2.x() + e0.x() * v2.z();	if (p0 < p2) {		pMin = p0;		pMax = p2;	} else {		pMin = p2;		pMax = p0;	}	rad = fe.z() * boxhalfsize.x() + fe.x() * boxhalfsize.z();	if (pMin > rad || pMax < -rad)		return 0;	p1 = e0.y() * v1.x() - e0.x() * v1.y();	p2 = e0.y() * v2.x() - e0.x() * v2.y();	if (p2 < p1) {		pMin = p2;		pMax = p1;	} else {		pMin = p1;		pMax = p2;	}	rad = fe.y() * boxhalfsize.x() + fe.x() * boxhalfsize.y();	if (pMin > rad || pMax < -rad)		return 0;	fe = e1.getAbs();	p0 = e1.z() * v0.y() - e1.y() * v0.z();	p2 = e1.z() * v2.y() - e1.y() * v2.z();	if (p0 < p2) {		pMin = p0;		pMax = p2;	} else {		pMin = p2;		pMax = p0;	}	rad = fe.z() * boxhalfsize.y() + fe.y() * boxhalfsize.z();	if (pMin > rad || pMax < -rad)		return 0;	p0 = -e1.z() * v0.x() + e1.x() * v0.z();	p2 = -e1.z() * v2.x() + e1.x() * v2.z();	if (p0 < p2) {		pMin = p0;		pMax = p2;	} else {		pMin = p2;		pMax = p0;	}	rad = fe.z() * boxhalfsize.x() + fe.x() * boxhalfsize.z();	if (pMin > rad || pMax < -rad)		return 0;	p0 = e1.y() * v0.x() - e1.x() * v0.y();	p1 = e1.y() * v1.x() - e1.x() * v1.y();	if (p0 < p1) {		pMin = p0;		pMax = p1;	} else {//.........这里部分代码省略.........

bool FloatRect::contains(const FloatRect& other) const{    return x() <= other.x() && maxX() >= other.maxX()        && y() <= other.y() && maxY() >= other.maxY();}

//-----------------------------------------------------------------------------// Function: setBottomCoordinate()//-----------------------------------------------------------------------------void AddressSpaceVisualizationItem::setBottomCoordinate(qreal yCoordinate) {	qreal width = rect().width();	qreal height = yCoordinate - y();	setRect(0, 0, width, height);	VisualizerItem::reorganizeChildren();}

	void system::set_geometry(const bool init) 	{		const double dt_max = 1.0/512;		scheduler = Scheduler(dt_max);		int np;		float lx, ly, lz;		FILE *fin = NULL;		if (myproc == 0)		{			float wp;			fin = fopen(fin_data, "r");			int ival;			size_t nread;			nread = fread(&ival, sizeof(int), 1, fin);		assert(ival == 2*sizeof(int));			nread = fread(&np, sizeof(int), 1, fin);			nread = fread(&wp, sizeof(float), 1, fin);			nread = fread(&ival, sizeof(int), 1, fin);		assert(ival == 2*sizeof(int));						nread = fread(&ival, sizeof(int), 1, fin);		assert(ival == 3*sizeof(float));			nread = fread(&lx, sizeof(float), 1, fin);			nread = fread(&ly, sizeof(float), 1, fin);			nread = fread(&lz, sizeof(float), 1, fin);			nread = fread(&ival, sizeof(int), 1, fin);		assert(ival == 3*sizeof(float));			fprintf(stderr, " np= %d  wp= %g /n",np, wp);			fprintf(stderr, " lx= %g  ly= %g  lz= %g /n", lx, ly, lz);		}		MPI_Bcast(&lx,  1, MPI_FLOAT, 0, MPI_COMM_WORLD);		MPI_Bcast(&ly,  1, MPI_FLOAT, 0, MPI_COMM_WORLD);		MPI_Bcast(&lz,  1, MPI_FLOAT, 0, MPI_COMM_WORLD);		t_end   = 0.2;		n_restart = 2;		dt_restart = dt_max;		dt_dump = 0.01;		di_log = 100;		global_n = local_n = 0;//		eulerian = true;		const vec3 rmin(0.0);		const vec3 rmax(lx, ly, lz);		global_domain = boundary(rmin, rmax);		global_domain_size = global_domain.hsize() * 2.0;		const vec3 Len3 = global_domain.hsize() * 2.0;		pfloat<0>::set_scale(Len3.x);		pfloat<1>::set_scale(Len3.y);		pfloat<2>::set_scale(Len3.z);		if (myproc == 0) 		{			ptcl.resize(np);			const int nx = (int)std::pow(np, 1.0/3.0);			const dvec3 dr = dvec3(Len3.x/nx, Len3.y/nx, Len3.z/nx);			const real rmax = dr.abs() * 1.0;			fprintf(stderr, "dr= %g %g %g /n", dr.x, dr.y, dr.z);			local_n  = ptcl.size();			global_n = local_n;			{				std::vector<float> x(local_n), y(local_n), z(local_n);				size_t nread;				int ival;				nread = fread(&ival, sizeof(int), 1, fin); assert(ival == local_n*(int)sizeof(float));				nread = fread(&x[0], sizeof(float), local_n, fin);				assert((int)nread == local_n);				nread = fread(&ival, sizeof(int), 1, fin); assert(ival == local_n*(int)sizeof(float));								nread = fread(&ival, sizeof(int), 1, fin); assert(ival == local_n*(int)sizeof(float));				nread = fread(&y[0], sizeof(float), local_n, fin);				assert((int)nread == local_n);				nread = fread(&ival, sizeof(int), 1, fin); assert(ival == local_n*(int)sizeof(float));								nread = fread(&ival, sizeof(int), 1, fin); assert(ival == local_n*(int)sizeof(float));				nread = fread(&z[0], sizeof(float), local_n, fin);				assert((int)nread == local_n);				nread = fread(&ival, sizeof(int), 1, fin); assert(ival == local_n*(int)sizeof(float));				for (int i = 0; i < local_n; i++)				{					const dvec3 vel(0.0, 0.0, 0.0);					ptcl[i] = Particle(x[i], y[i], z[i], vel.x, vel.y, vel.z, i);					ptcl[i].rmax = rmax;					ptcl[i].unset_derefine();				}			}//.........这里部分代码省略.........

 /**  * to draw stuff and interface with QT  */ QPointF toQPointF() const { return QPointF(x(), y()); }

 operator Packet::Point() const {     Packet::Point out;     out.set_x(x());     out.set_y(y());     return out; }

 float cross(const Point& other) const {     return x() * other.y() - y() * other.x(); }

 std::string toString() const {     std::stringstream str;     str << "Point(" << x() << ", " << y() << ")";     return str.str(); }

 /** returns the perpendicular to the point, Counter Clockwise */ Point perpCCW() const { return Point(-y(), x()); }

 /** returns the perpendicular to the point, Clockwise */ Point perpCW() const { return Point(y(), -x()); }

 /** * Returns the angle of this point in radians CCW from +X. */ float angle() const { return atan2(y(), x()); }

/*!  Draw dots  /param painter Painter  /param xMap x map  /param yMap y map  /param from index of the first point to be painted  /param to index of the last point to be painted  /sa draw(), drawCurve(), drawSticks(), drawLines(), drawSteps()*/void QwtPlotCurve::drawDots(QPainter *painter,    const QwtScaleMap &xMap, const QwtScaleMap &yMap,     int from, int to) const{    const QRect window = painter->window();    if ( window.isEmpty() )        return;    const bool doFill = d_data->brush.style() != Qt::NoBrush;    QwtPolygon polyline;    if ( doFill )        polyline.resize(to - from + 1);    if ( to > from && d_data->paintAttributes & PaintFiltered )    {        if ( doFill )           {            QPoint pp( xMap.transform(x(from)), yMap.transform(y(from)) );            QwtPainter::drawPoint(painter, pp.x(), pp.y());            polyline.setPoint(0, pp);            int count = 1;            for (int i = from + 1; i <= to; i++)            {                const QPoint pi(xMap.transform(x(i)), yMap.transform(y(i)));                if ( pi != pp )                {                    QwtPainter::drawPoint(painter, pi.x(), pi.y());                    polyline.setPoint(count, pi);                    count++;                    pp = pi;                }            }            if ( int(polyline.size()) != count )                polyline.resize(count);        }        else        {            // if we don't need to fill, we can sort out            // duplicates independent from the order            PrivateData::PixelMatrix pixelMatrix(window);            for (int i = from; i <= to; i++)            {                const QPoint p( xMap.transform(x(i)),                    yMap.transform(y(i)) );                if ( pixelMatrix.testPixel(p) )                    QwtPainter::drawPoint(painter, p.x(), p.y());            }        }    }    else    {        for (int i = from; i <= to; i++)        {            const int xi = xMap.transform(x(i));            const int yi = yMap.transform(y(i));            QwtPainter::drawPoint(painter, xi, yi);            if ( doFill )                polyline.setPoint(i - from, xi, yi);        }    }    if ( doFill )    {        if ( d_data->paintAttributes & ClipPolygons )            polyline = QwtClipper::clipPolygon(painter->window(), polyline);        fillCurve(painter, xMap, yMap, polyline);    }}

void Edit::resizeEvent(QResizeEvent *){    button->setGeometry((x() + width() + (height() * 0.4)) - height(),                        y() + (height() * 0.3),height() * 0.4,height() * 0.4);}

bool FloatRect::isExpressibleAsIntRect() const{    return isWithinIntRange(x()) && isWithinIntRange(y())        && isWithinIntRange(width()) && isWithinIntRange(height())        && isWithinIntRange(maxX()) && isWithinIntRange(maxY());}

bool FloatRect::contains(const FloatPoint& point, ContainsMode containsMode) const{    if (containsMode == InsideOrOnStroke)        return contains(point.x(), point.y());    return x() < point.x() && maxX() > point.x() && y() < point.y() && maxY() > point.y();}

void BtModuleManagerDialog::saveDialogSettings() {    CBTConfig::set(CBTConfig::bookshelfWidth, size().width());    CBTConfig::set(CBTConfig::bookshelfHeight, size().height());    CBTConfig::set(CBTConfig::bookshelfPosX, x());    CBTConfig::set(CBTConfig::bookshelfPosY, y());}

    /**     * see operator+     * this modifies the value instead of returning a new value     */    Point& operator+=(Point other) {        x() += other.x();        y() += other.y();        return *this;    }

auto Curry=[](auto x,auto y){return[=]{auto i=x();while(i--)y();};};#include <iostream>int main() {    auto foo = Curry([]{return 12;}, []{std::cout << "y/n";});    foo();}

/*!  /brief Draw lines  If the CurveAttribute Fitted is enabled a QwtCurveFitter tries  to interpolate/smooth the curve, before it is painted.  /param painter Painter  /param xMap x map  /param yMap y map  /param from index of the first point to be painted  /param to index of the last point to be painted  /sa setCurveAttribute(), setCurveFitter(), draw(),       drawLines(), drawDots(), drawSteps(), drawSticks()*/void QwtPlotCurve::drawLines(QPainter *painter,    const QwtScaleMap &xMap, const QwtScaleMap &yMap,     int from, int to) const{    int size = to - from + 1;    if ( size <= 0 )        return;    QwtPolygon polyline;    if ( ( d_data->attributes & Fitted ) && d_data->curveFitter )    {        // Transform x and y values to window coordinates        // to avoid a distinction between linear and        // logarithmic scales.#if QT_VERSION < 0x040000        QwtArray<QwtDoublePoint> points(size);#else        QPolygonF points(size);#endif        for (int i = from; i <= to; i++)        {            QwtDoublePoint &p = points[i];            p.setX( xMap.xTransform(x(i)) );            p.setY( yMap.xTransform(y(i)) );        }        points = d_data->curveFitter->fitCurve(points);        size = points.size();        if ( size == 0 )            return;        // Round QwtDoublePoints to QPoints        // When Qwt support for Qt3 has been dropped (Qwt 6.x)        // we will use a doubles for painting and the following        // step will be obsolete.        polyline.resize(size);        const QwtDoublePoint *p = points.data();        QPoint *pl = polyline.data();        if ( d_data->paintAttributes & PaintFiltered )        {            QPoint pp(qRound(p[0].x()), qRound(p[0].y()));            pl[0] = pp;            int count = 1;            for (int i = 1; i < size; i++)            {                const QPoint pi(qRound(p[i].x()), qRound(p[i].y()));                if ( pi != pp )                {                    pl[count++] = pi;                    pp = pi;                }            }            if ( count != size )                polyline.resize(count);        }        else        {            for ( int i = 0; i < size; i++ )            {                pl[i].setX( qRound(p[i].x()) );                pl[i].setY( qRound(p[i].y()) );            }        }    }    else    {        polyline.resize(size);        if ( d_data->paintAttributes & PaintFiltered )        {            QPoint pp( xMap.transform(x(from)), yMap.transform(y(from)) );            polyline.setPoint(0, pp);            int count = 1;            for (int i = from + 1; i <= to; i++)            {                const QPoint pi(xMap.transform(x(i)), yMap.transform(y(i)));                if ( pi != pp )                {//.........这里部分代码省略.........

	QString Rect::toString() const	{        return QString("Rect {x: %1, y: %2, width: %3, height: %4}").arg(x()).arg(y()).arg(width()).arg(height());	}

 /** computes magnitude squared this is faster than mag() @return the magnitude squared */ float magsq() const { return x() * x() + y() * y(); }