Java

public class Krog
{
  private double polmer;
  
  private double obseg()
  {
    return 2*this.polmer*Math.PI;
  }
  
  private double ploscina()
  {
    return this.polmer*Math.PI*Math.PI;
  }
  
  public void setPolmer(double polmer)
  {
    this.polmer = polmer;
  }
  
  public String toString()
  {
    return 
        "Krog:" +
        "\n\tpolmer:\t" + this.polmer +
        "\n\tobseg:\t" + this.obseg() +
        "\n\tploscina:\t" + this.ploscina();
  }
}

public class Glavni
{
  public static void main(String[] args)
  {
    Krog krog = new Krog();
    for(int i = 1;i < 100;i = i + 5)
    {
      krog.setPolmer(i);
      System.out.println(krog);
    }
  }
}