Checking for same data type

Question

Im trying to do basic Math.sqrt(x*x +y*y) calculations with inputted 3 variables but want a simply error checking if-statement to find out if the variables are compatible, as in inputted 2,3,F...F will not work. Any help?                                                                                                                                                                                                                                                                                                                                                                                                                                                           

Answer 1

This works, and it guards against overflow when it calculates the square root of the sum of squares:
public class SquareRooter
    public static void main(String [] args)
        if (args.length > 1)
            try
                double x = Double.parseDouble(args[0]);
                double y = Double.parseDouble(args[1]);
                System.out.println("x              : " + x);
                System.out.println("y              : " + y);
                System.out.println("sqrt(x*x + y*y): " + SquareRooter.squareRoot(x, y));
            catch (NumberFormatException e)
                e.printStackTrace(System.err);
        else
            System.out.println("Usage: SquareRooter <x> <y>");
    public static double squareRoot(final double x, final double y)
        double xabs = Math.abs(x);
        double yabs = Math.abs(y);
        if (xabs > yabs)
            double ratio = yabs/xabs;
            return xabs*Math.sqrt(1.0 + ratio*ratio);
        else
            double ratio = xabs/yabs;
            return yabs*Math.sqrt(1.0 + ratio*ratio);
}MOD