class DvouDObrazec { //- dedeni konstruktoru
  private double width; 
  private double height; 
 
  DvouDObrazec() { //-implicitni konstruktor
    width = height = 0.0; 
  } 
 
   DvouDObrazec(double w, double h) { //-konstr.se 2 parametry
    width = w; 
    height = h; 
  } 
  
  DvouDObrazec(double x) { //-konstr.s 1 parametrem
    width = height = x; 
  } 
 
  double getWidth() { return width; } 
  double getHeight() { return height; } 
  void setWidth(double w) { width = w; } 
  void setHeight(double h) { height = h; } 
  void showDim() { 
    System.out.println("sirka a vyska jsou " + 
                       width + " a " + height); 
  } 
} 
 
class Trojuhelnik extends DvouDObrazec { //-podtrida trojuhelnik
  private String style; 
   
  Trojuhelnik() { //-implicitni konstruktor
    super(); 
    style = ""; 
  } 
 
  Trojuhelnik(String s, double w, double h) { //-konstr. se 3 param.
    super(w, h); // vola konstructor nadtridy
 
    style = s;  
  } 
 
  Trojuhelnik(double x) { 
    super(x); //- vola konstructor nadtridy  
 
    style = "stejne siroky jako vysoky";  
  } 
 
  double area() { 
    return getWidth() * getHeight() / 2; 
  } 
 
  void showStyle() { 
    System.out.println("Trojuhelnik je " + style); 
  } 
} 
 
class ObrazceKon { 
  public static void main(String args[]) { 
    Trojuhelnik t1 = new Trojuhelnik(); 
    Trojuhelnik t2 = new Trojuhelnik("placaty", 20.0, 2.0); 
    Trojuhelnik t3 = new Trojuhelnik(4.0); 
    
    System.out.println("informace pro t1: "); 
    t1.showStyle(); 
    t1.showDim(); 
    System.out.println("plocha = " + t1.area()); 
 
    System.out.println(); 
 
    System.out.println("informace pro t2: "); 
    t2.showStyle(); 
    t2.showDim(); 
    System.out.println("plocha = " + t2.area()); 
 
    System.out.println(); 
 
    System.out.println("informace pro t3: "); 
    t3.showStyle(); 
    t3.showDim(); 
    System.out.println("plocha = " + t3.area()); 
 
    System.out.println(); 
  } 
}