Chapter 12.1 (NumberFormatException) Listing 7.9, Calculator.java, is a simple command line calculator. Note that the program terminates if any operand is nonnumeric. Write a program with an exception handler that deals with nonnumeric operands;

then write another program without using an exception handler to achieve the same objective. Your program should display a message that informs the user of the wrong operand type before exiting. i am having trouble with write another program without using an exception handler .

here is my code

/**12.1 (NumberFormatException) Listing 7.9, Calculator.java, is a simple command line calculator. Note that the program terminates if any operand is nonnumeric. Write a program with an exception handler that deals with nonnumeric operands; then write another program without using an exception handler to achieve the same objective. Your program should display a message that informs the user of the wrong operand type before exiting */ import java.util.Scanner; import java.util.Scanner; public class SimpleCalculator { public static void main(String[] args) { System.out.println("Please calculation"); Scanner scanner = new Scanner(System.in); int left = scanner.nextInt(); String op = scanner.next(); int right = scanner.nextInt(); System.out.println(compute(left, op, right)); } private static int compute(int left, String op, int right) { switch (op.charAt(0)) { case '+': return left + right; case '-': return left - right; case '*': return left * right; case '/': return left / right; } throw new IllegalArgumentException("Unknown operator:" + op); } }

Command prompt C exercise java Exercisel 2-01 4 5 H 5 c exercise jaua Exercise 2-01 4 5 c:\exercise jaua Exercise12-01 4x 5 Wrong Input: 4x c: exercise