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📜 WAYPOINT LESSON

Checkpoint: The Point Class

⭐ beginner⏳ 45 min read📍 Lesson 34 of 180

An immutable coordinate type: final fields, factory method, translating without mutation, and geometric equality.

The Point class — a coordinate with rules.

Inside Solution, write static class Point with:

  1. private final int x; private final int y; — an immutable point.
  2. A constructor taking (int x, int y).
  3. Getters getX(), getY().
  4. public Point translate(int dx, int dy) — returns a NEW Point moved by the delta (the original must be untouched — immutability!).
  5. public double distanceTo(Point other) — Euclidean distance (Math.hypot(dx, dy) is fine).
  6. static Point origin() — a factory returning new Point(0, 0).
  7. public boolean equalsPoint(Point other) — same x AND same y. (The real equals/hashCode contract arrives in Module 9; this method-side version keeps the focus on fields.)

Immutability is the heart of this checkpoint: after Point p2 = p1.translate(5, 0);, p1 must still have its original coordinates, and p2 must be a different object with the new ones.