| 7 | point3d(double _x, double _y, double _z) |
| 8 | : x(_x), y(_y), z(_z) {} |
| 9 | point3d operator+(P(p)) const { |
| 10 | return point3d(x + p.x, y + p.y, z + p.z); } |
| 11 | point3d operator-(P(p)) const { |
| 12 | return point3d(x - p.x, y - p.y, z - p.z); } |
| 13 | point3d operator-() const { |