public class Rond implements Form {
  private double diametre;
  
  Rond(double d) throws EuclideException {
    if ( d <= 0) {
      System.err.println("Les ronds ont un diametre positif");
      throw new EuclideException();
    }
    diametre=d;
  }
  
  public double getDiametre() 
  {
    return diametre;
  }
  
  public double perimeter () {
    return Math.PI*diametre ;
  }
  
  public double area() {
    return Math.PI*diametre*diametre/4;
  }

  public String toString() {
    return "Rond " + diametre;
  }
  
  public static void main(String [] args){
    Rond r;
    try{r=new Rond(-15);}
    catch (EuclideException e)
      {r=null;}
  }
}