How to multiply Roman Number string with a double in Java?

Question

i am new to a java program and i have a homework where when i get input from a user as an string, i have to convert it to a double and multiple it with a .11111 using a switch decision structure.

A string input from user has to be a number in roman numeral which is I, II, III, IV, and so on....


//This is my program
package practiceNum;
import java.util.Scanner;

public class practiceNum{
    class stastic void main(String[] args){

    String num_In_Roman;    //declare a string

    Scanner keyboard = new Scanner(System.in);  //read input words

    System.out.println("Enter a roman numerals from I to X: "); //asking user input
    num_In_Roman = keyboard.nextLine();

    switch(num_In_Roman){

    case "I":
    break;

    case "II":
    break;

    //and so on until 10 (X) in roman numerals. 
    default:
        System.out.println("Invalid Number!");
    }

    //end of body program here
    }

}



Here's what i did to calculate my math but still giving me an error.

Double value = Double.parseDouble(num_In_Roman); //convert string into double

case "I":
value *= .111111;
System.out.println(value);
break;


someone help please.

Answer 1

This is the bad way, but this is what you can do:

case "I":
value = 1 * .111111;
System.out.println(value);
break;

case "II":
value = 2 * .111111;
System.out.println(value);
break;