Do I have to join al the three classes together? How do I add the main METHOD then? The programe are under. How can it then be interrupted with "throw new error();" as well give information to the user?
ANSWER
public class Parallelogramm {
private Koordinate k1,k2;
private double a,b,h;
private double alpha;
public Parallelogramm(Koordinate k1, Koordinate k2, double alpha) {
this.k1 = k1;
this.k2 = k2;
this.alpha = alpha;
h = Math.abs(k2.getY()-k1.getY());
b = h / Math.sin(alpha);
a = Math.abs(k2.getX()-k1.getX()) - b*Math.cos(alpha);
}
public Parallelogramm(Koordinate k1, Koordinate k2, int alpha) {
this(k1,k2,alpha*Math.PI/180);
}
public double getA() { return a; }
public double getB() { return b; }
public double getH() { return h; }
public double getAlpha() { return alpha; }
public double Area() {
return a*h;
}
public double Circumfrence() {
return 2*(a+b);
}
}
public class Rectangle extends Parallelogramm {
public Rectangle(Koordinate k1, Koordinate k2) {
super(k1,k2,90); // alternativ: super(k1,k2,Math.PI/2);
}
}
public class Square extends Rectangle {
public Square(Koordinate k1, Koordinate k2) {
super(k1,k2);
if (Math.abs(this.getSeite1()-this.getSeite2())>0.0001) {
throw new Error("The Coordinates do not describe a Square");
}
}
}
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