MoneyConverter.java

[Ian Plätschisch]

I am currently studying for a final in a Java course I am taking, so I decided to write some Talossa-related programs. This one can convert dollars to louise and vice versa.

import java.util.Scanner;
public class MoneyConverter {
    public static void main(String[] args) {
        Scanner keyboard = new Scanner(System.in);
        System.out.println("Enter \"1\" to convert from dollars to louise or \"2\" to convert from louise to dollars");
        int input = keyboard.nextInt();
        while (input != 1 && input != 2) {
            System.out.println("Invalid input. Enter a valid input");
            input = keyboard.nextInt();
        }
        if (input == 1) {
            System.out.println();
            System.out.print("Enter the amount of dollars: ");
            double dollars = keyboard.nextDouble();
            double louise = dollars / 1.5;
            int wholeLouise = (int)louise;
            double bence = (louise - wholeLouise) * 60;
            int roundedBence = (int)bence;
            if (bence - roundedBence >= .5) {
                roundedBence++;
            }
            if (roundedBence == 60) {
                wholeLouise++;
                roundedBence = 0;
            }
            if (roundedBence == 0) {
                System.out.println("Amount of louise: ℓ" + wholeLouise);
            }
            else {
                System.out.println("Amount of louise: " + wholeLouise + "¤" + roundedBence);
            }
        }
        else {
            System.out.println();
            System.out.print("Enter the number of whole louise: ");
            int louise = keyboard.nextInt();
            System.out.print("Enter the number of bence: ");
            int bence = keyboard.nextInt();
            double dollars = louise * 1.5 + bence * .025;
            int wholeDollars = (int)dollars;
            double cents = (dollars - wholeDollars) * 100;
            int roundedCents = (int)cents;
            if (cents - roundedCents >= .5) {
                roundedCents++;
            }
            if (roundedCents == 100) {
                wholeDollars++;
                roundedCents = 0;
            }
            if (roundedCents == 0) {
                System.out.println("Amount of dollars: $" + wholeDollars);
            }
            else {
                System.out.println("Amount of dollars: $" + wholeDollars + "." + roundedCents);
            }
        }
    }
}

Attachments:

MoneyConverter.java (1.79 KB)

[Lüc da Schir]

Looks good, I think, except that you aren't handling any exceptions. I don't know if your course covered those, but it's good practice to surround every (block of) code that may throw an exception with try{} and catch{} statements. In your case, for example, you'd do that on all instances where you're prompting the user for an integer (or double), as if the user types something that is not an integer, Java would throw an InputMismatchException and immediately block execution. Using try{} and catch{} allows you to write code to handle such unexpected instances and, in your case, prompt the user for a number again instead of crashing the whole thing.

Also, I've noticed you use "println();" and then "print(...);" when you want to print to a new line. I don't know if Java optimizes for that on bytecode generation (or whatever Java's faux-compiling is called), but if you don't already know it, you can simply use the "\n" escape sequence to insert a new line whenever you want - so "print(\n...);" would do the same thing you wrote in one less line.

[Ian Plätschisch]

Dec 8, 2018 3:40:52 GMT -6 Lüc da Schir said:

Looks good, I think, except that you aren't handling any exceptions. I don't know if your course covered those, but it's good practice to surround every (block of) code that may throw an exception with try{} and catch{} statements. In your case, for example, you'd do that on all instances where you're prompting the user for an integer (or double), as if the user types something that is not an integer, Java would throw an InputMismatchException and immediately block execution. Using try{} and catch{} allows you to write code to handle such unexpected instances and, in your case, prompt the user for a number again instead of crashing the whole thing.

We did learn some basic error-handling techniques but not try and catch.

Also, I've noticed you use "println();" and then "print(...);" when you want to print to a new line. I don't know if Java optimizes for that on bytecode generation (or whatever Java's faux-compiling is called), but if you don't already know it, you can simply use the "\n" escape sequence to insert a new line whenever you want - so "print(\n...);" would do the same thing you wrote in one less line.

We did learn about this but using another println feels more natural to me. If I am ever code golfing I will keep this in mind.