public class MyMathOperations
{
  public int factorial(int n)
     {
       int result = 1;
       int i;
       for (i = 1; i <= n; i++)
         {
           result = result * i;
         }
       return result;
      }
  public double distanceCalculation(double x1, double y1, double x2, double y2)
  {
    double result;
    result = Math.sqrt(Math.pow((x2 - x1), 2) + Math.pow((y2 - y1), 2));
    return result;
  }
  
  public static double truncate(double x)
{
    double z = Math.round(x*Math.pow(10, 10));
    long y=(long)z;
    return (double)y*Math.pow(10, -10);
}
  
}