//Method for my team by Leyca Besarra, Paul Davis and Ibrahim Alshubaily

//This method is for processing userInput for coefficients a, b, and c of the quadratic equation via JOptionPane
//this is meant to be used with doubles.
//this needs 'import javax.swing.JOptionPane;'
//the method should be used similarly to the lines below, but for the 3 coefficients.
//double a = inHandler("For the equation, Ax^2+Bx+C = 0, please enter the coefficient A");
//double b = inHandler("For the equation, Ax^2+Bx+C = 0, please enter the coefficient B");
//double c = inHandler("For the equation, Ax^2+Bx+C = 0, please enter the coefficient C");
//make the variable(some sorts of doubles) invoke the method name inHandler, and place the desired message to be shown to the user within (" ")


    public static double inHandler(String prompt){
        double returnValue = 0;
        boolean tryAgain = false;
        do {
            String s = JOptionPane.showInputDialog(prompt);
            try {
                returnValue = Double.parseDouble(s);
            } catch (NumberFormatException e){
                returnValue = Double.NaN;
                if (Double.isNaN(returnValue)){
                    JOptionPane.showMessageDialog(null, "you have entered something I can't understand, please try again.");
                }
                tryAgain = true;
            }
        } while (tryAgain);
        return returnValue;
    } //end of inHandler