Exercise 0 - Circle and Point

Tips

this and CLASS

When we encapsulate a class, it is recommended to use this before any instance field in this class and CLASS. before any static/class field. This is to differentiate them from the local variables.

The practice of "Tell, Don't Ask"

When we design the .contains() method attached to a circle, we should keep the principle of "Tell, don't ask" in mind. So, our implementation will be:

Circle.java

public boolean contains(Point p) {
  return this.c.distanceTo(p) <= this.r;
}

Point.java

import java.lang.Math;

public double distanceTo(Point p) {
  double x = this.x - p.x;
  double y = this.y - p.y;
  return Math.sqrt(x * x + y * y);
}