class Ponto2D { private int x; private int y; public Ponto2D(int x, int y) { this.x = x; this.y = y; } public Ponto2D( ) { this(0,0); } public double distancia(Ponto2D p) { double distX = p.x - x; double distY = p.y - y; return(Math.sqrt(distX*distX + distY*distY)); } } class Ponto3D extends Ponto2D { private int z; public Ponto3D(int x, int y, int z) { super(x, y); this.z = z; } public Ponto3D( ) { z = 0; } public static void main(String[] args) { Ponto2D ref2 = new Ponto2D(); Ponto2D p2 = new Ponto2D(1,1); System.out.println("Distancia2: " + p2.distancia(ref2)); Ponto3D p3 = new Ponto3D(1,2,3); System.out.println("Distancia3: " + p3.distancia(ref2)); } }