SalesLoop.java

import java.util.Scanner;

/**
 * Runs a loop that lets a user enter a number.
 * It validates the input, then multiply the number by 10 and stores the result in a variable named 'sales'.
 * The loop iterates if the input contains a value less than 100.
 * The loop terminates with a response to the user if the value entered is 100 or greater and ends the program.
 */
public class SalesLoop {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        // Initialize the variables.
        // value is initialized to -1 so do-while loop will execute at least once.
        float value = -1.0f;
        float sales;
        String input;

        // Loop that repeats until the input is a valid number greater than 100.
        do { System.out.print("Enter a number: ");
            input = scanner.nextLine();
            // Check input is a valid non-negative number and assign it to value.
            // RegEx pattern matches any decimal number (with or without a decimal point) in US n.nn or EU n,nn format.
            if (input.matches("(\\d)*(\\.|,)?\\d+")) {
                value = Float.parseFloat(input.replace(",","."));
                // Check value is less than 100 and multiply by 10 and assign it to sales if it is.
                if (value < 100.0f) {
                    sales = value * 10.0f;
                    System.out.printf("Sales: $%.2f%n", sales);
                }
            }
        // Continue loop if input was either less than 100 or not a number.
        } while (value <= 100);

        // Inform the user the value entered was over 100.
        System.out.printf("Value entered: \"%s\" is greater than 100.%n", input);
        scanner.close();
    }
}