Black Scholes java in pgm

BlackScholes.java

               public class BlackScholes

            {

    public static double callPrice(double s, double x, double r, double sigma, double t)

   {

        double a = (Math.log(s/x) + (r + sigma * sigma/2) * t) / (sigma * Math.sqrt(t));

        double b = a - sigma * Math.sqrt(t);

        return s * Gaussian.Phi(a) - x * Math.exp(-r * t) * Gaussian.Phi(b);

    }

             public static void main(String[] args)

              {

        double s     = Double.parseDouble(args[0]);

        double x     = Double.parseDouble(args[1]);

        double r     = Double.parseDouble(args[2]);

        double sigma = Double.parseDouble(args[3]);

        double t     = Double.parseDouble(args[4]);

        System.out.println(callPrice(s, x, r, sigma, t));

    }

}