import java.util.Scanner;

public class main {

    static double accumulator = 0;

    public static void main(String [] args)
    {
        boolean loop = true;

        do{
            try
            {
                System.out.println("To start please select an operation");
                System.out.println("Press + for addition");
                System.out.println("Press - for subtraction");
                System.out.println("Press * for multiplication");
                System.out.println("Press / for division");
                System.out.println("Press R to reset the accumulator to 0");
                System.out.println("Press P to power off the calculator");

                Scanner keyboard = new Scanner(System.in);

                String input = keyboard.next();

                unknownOperator(input);

                switch(input){
                    case "+":
                        System.out.println("Type in one number:");
                        String x = keyboard.next();
                        NumberFormatException(x);
                        double input1 = Double.parseDouble(x);
                        accumulator += input1;
                        System.out.println("The sum is: " + accumulator);
                        break;

                    case "-":
                        System.out.println("Type in one number:");
                        String x1 = keyboard.next();
                        NumberFormatException(x1);
                        double input2 = Double.parseDouble(x1);
                        accumulator -= input2;
                        System.out.println("The difference is: " + accumulator);
                        break;

                    case "*":
                        System.out.println("Type in one number:");
                        String x2 = keyboard.next();
                        NumberFormatException(x2);
                        double input3 = Double.parseDouble(x2);
                        accumulator -= input3;
                        System.out.println("The product is: " + accumulator);
                        break;

                    case "/":
                        System.out.println("Type in one number:");
                        String x3 = keyboard.next();
                        NumberFormatException(x3);
                        double input4 = Double.parseDouble(x3);
                        accumulator -= input4;
                        divideByZero(input4);
                        System.out.println("The product is: " + accumulator);
                        break;

                    case "R":
                        accumulator = 0;
                        System.out.println("Accumulator has been set to 0");
                        break;

                    case "P":
                        System.out.println("Shutting off calculator");
                        break;




                }
            }

            catch(DivideByZeroException e)
            {
                System.out.println(e.getMessage());
            }

            catch(UnknownOperatorException e)
            {
                System.out.println(e.getMessage());
            }

            catch(NumberFormatException e)
            {
                System.out.println(e.getMessage());
            }

        }


        while(loop == true);



    }

    public static void divideByZero(double valueTwo) throws DivideByZeroException
    {
        if(valueTwo == 0)
        {
            throw new DivideByZeroException("You cannot divide by zero, try again.");
        }

    }

    public static void unknownOperator(String sign) throws UnknownOperatorException
    {
        if(sign.equals("+") || sign.equals("-") || sign.equals("*") || sign.equals("/") || sign.equals("R") || sign.equals("P"))
        {

        } else {
            throw new UnknownOperatorException("That is an unrecognized symbol, try again.");
        }

        System.out.println("nice");
    }

    public static void NumberFormatException(String string) {
        if (string.equals("R")) {
            accumulator = 0;
            System.out.println("Accumulator has been set to 0");
        } else if (string.equals("P")) {
            System.out.println("Shutting off calculator");
            System.exit(0);
        }
    }
}