If the user enters any operator symbol other than , -, *, or /, then an UnknownOperatorException is thrown and the user is allowed to reenter that line of input. Define the class UnknownOperatorException as a subclass of the Exception class. Your program should also handle NumberFormatException if the user enters non-numeric data for the operand.

Explanation:

The following code is written in Java. It creates the UnknownOperatorException class and catches it if the user enters something other than the valid operators. If so it continues asking the user for a new input. Once a valid operator is entered, it exits the function and prints the operator.

import java.util.Scanner;

class {

   public static void main(String[] args) {

       char symbol = askForOperand();

       System.out.println("Operand: " + symbol);

   }

   public static char askForOperand() {

       Scanner in = new Scanner(System.in);

       try {

           System.out.println("Enter operator symbol: ");

           char symbol = in.nextLine().charAt(0);

           if ((symbol != '-') && (symbol != '*') && (symbol != '/')) {

               System.out.println(symbol);

               throw new UnknownOperatorException();

           } else {

               return symbol;

           }

       } catch (NumberFormatException | UnknownOperatorException e) {

           System.out.println("Not a valid operand");

           char symbol = askForOperand();

           return symbol;

       }

   }

}

class UnknownOperatorException extends Exception {

   public UnknownOperatorException() {

       System.out.println("Unknown Operator");

   }

}

answer; i believe the correct answer is (b) by using a multimeter;

well cos like a ds it doesn't really die out, unlike for example, fifa, they always come out with a new version, so lets say your fifa 18 is charging you to update the teams and stuff, so, if messi were to go to real madrid (never gonna happen) it would switch messi to the other team, until the owners of fifa come out with fifa 19, then the game would eventually stop updating, and back to the ds, it doesn't really stop working after sometime because there's lots of things that it could be used for, and idk if u know what i'm saying, but long story short, samsung, represents the ds, if they still work, and people love them but not the new version, the old version still works, so they don't really force people to buy new phones, get me?