Question

The Double.parseDouble() method requires a String argument, but it fails if the String cannot be converted to a floating-point number. Write an application in which you try accepting a double input from a user and catch a NumberFormatException if one is thrown. Te catch block forces the number to 0 and displays an appropriate error message. Following the catch block, display the number. Save the fle as TryToParseDouble.java.

Answer 1

Answer:

1. import java.util.Scanner;
2. public class TryToParseDouble {
4.    public static void main(String[] args) {
5.        Scanner input = new Scanner(System.in);
6.        double num;
8.        try{
9.            System.out.print("Input a number: ");
10.            num = Double.parseDouble(input.nextLine());
12.        }catch(NumberFormatException e){
13.            num = 0;
14.            System.out.println("Invalid input! It should be a number in double type");
15.        }
16.        System.out.println(num);
17.    }
18. }

Explanation:

Firstly, create a Scanner object to get user input (Line 5).

Next, create a try block and prompt user to input a number and use Double.parseDouble() method to convert the input to double type in the block (Line 8-10).

Next, create a catch block to catch a NumberFormatException. In the Catch block, set the num to zero and then print out a message to inform user about the invalid input (Line 12-14).

Lastly, display the number (Line 16).