задание1

#include <iostream>

using namespace std;

class Point3D {

private:

double x;

double y;

double z;

public:

Point3D() {x = 0.0; y = 0.0; z = 0.0;}

Point3D(double X, double Y, double Z) {x = X; y = Y; z = Z;}

Point3D(const Point3D& P) {x = P.x; y = P.y; z = P.z;}

Point3D projX(const Point3D& P) {return Point3D(P.x, 0.0, 0.0);}

Point3D projXY(const Point3D& P) {return pair(P.x, P.y, 0.0);}

Point3D operator+(Point3D P) {

Point3D Res;

Res.x = x+ P.x;

Res.y = y+ P.y;

Res.z = z+ P.z;

return Res;

}

};

int main() {

// your code goes here

}