simple vector thing

vector.cpp

#include <cmath>

class Vector {
    public:
        Vector() : x(0), y(0), z(0) {
        }
        Vector(double iX, double iY, double iZ) : x(iX), y(iY), z(iZ) {
        }

        double magnitude() const {
            return sqrt(x*x + y*y + z*z);
        }

        Vector &operator=(const Vector &rhs) {
            x = rhs.x;
            y = rhs.y;
            z = rhs.z;
            return (*this);
        }
        Vector operator+(const Vector &rhs) {
            return Vector(x + rhs.x, y + rhs.y, z + rhs.z);
        }
        Vector operator+=(const Vector &rhs) {
            return (*this) = (*this) + rhs;
        }

        double x;
        double y;
        double z;
};