class Instrucciones {
   public static void main(String [] args) {
      int i,j;
      for (i=0;i<20;i++) { 
	System.out.print(" "+i);
      }//for
      System.out.println();
      if (i==20) {
        System.out.println("Fin de ciclo!");
      }//if
      long x=35;
      while (x>30) x--;
      double y = Math.PI*x;
      System.out.println(y*x);
      int flag= 3;
      switch (flag) {
        case 3: System.out.println("verdadero"); break;
        default: System.out.println("falso");
      }//switch
   }//main

}//class