public void randomIntFinder(Scanner scanner)
{
    try
    {
        System.out.printf("Enter 2 numbers and get a random " + "integer between those two numbers!\n");
        scanner = new Scanner(System.in);
        System.out.printf("Enter the first integer: ");
        int intRange1 = scanner.nextInt();
        System.out.printf("Enter the next integer: ");
        int intRange2 = scanner.nextInt();

        Random random = new Random();
        int randomInt = random.nextInt(intRange1, intRange2 + 1);
        System.out.printf("Random number between %d and %d: %d\n\n", intRange1, intRange2, randomInt);
    }
    catch (IllegalArgumentException e)
    {
        System.out.printf("Error: The last number must be greater than the first!\n");
    }
    catch (InputMismatchException e)
    {
        System.out.printf("Error: Must be type integer!\n");
    }
}

public void doubleAddingCalculator(Scanner scanner)
{
    try
    {
        System.out.printf("Enter 2 decimals to get their sum!\n");
        System.out.printf("Enter the first double: ");
        double firstDouble = scanner.nextDouble();
        System.out.printf("Enter the next double: ");
        double lastDouble = scanner.nextDouble();
        
        firstDouble += lastDouble;
        
        System.out.printf("Sum: %f\n\n", firstDouble);
    }
    catch (InputMismatchException e)
    {
        System.out.printf("Error: Must be type double!\n");  
    }
}

public void getRomanNumerals(Scanner scanner)
{
    System.out.print("Enter any number: ");
    int num = scanner.nextInt();
   
    String numeral = convertRomanNumeral(num);
    
    System.out.print("Roman numeral: " + numeral);
}


/*
 * Takes the number passed in and returns a string of the Roman Numeral 
 */
public static String convertRomanNumeral(int number)
{
    // calculates number of 1000s
    int _1000 = (number / 1000);
    String value = numToRN(_1000 * 1000);
    number -= _1000 * 1000;
    
    
    // calculates number of 100s
    int _100 = (number / 100);
    String value1 = numToRN(_100 * 100);
    number -= _100 * 100;
    
    
    // calculates number of 10s
    int _10 = (number / 10);
    String value2 = numToRN(_10 * 10);
    number -= _10 * 10;
    
    
    // calculates number of 1s
    int _1 = number;
    String value3 = numToRN(_1);
    number -= _1;
    
    return value + value1 + value2 + value3;
    


}

/*
 * A table of all the 
 */
private static String numToRN (int number)
{
    switch (number)
    {
    case 1: return "I";
    case 2: return "II";
    case 3: return "III";
    case 4: return "IV";
    case 5: return "V";
    case 6: return "VI";
    case 7: return "VII";
    case 8: return "VIII";
    case 9: return "IX";
    
    case 10: return "X";
    case 20: return "XX";
    case 30: return "XXX";
    case 40: return "XL";
    case 50: return "L";
    case 60: return "LX";
    case 70: return "LXX";
    case 80: return "LXXX";
    case 90: return "XC";
    
    case 100: return "C";
    case 200: return "CC";
    case 300: return "CCC";
    case 400: return "CD";
    case 500: return "D";
    case 600: return "DC";
    case 700: return "DCC";
    case 800: return "DCCC";
    case 900: return "CM";
    
    case 1000: return "M";
    case 2000: return "MM";
    case 3000: return "MMM";

    }
    
    return "";
}

Scanner scanner = new Scanner(System.in);
        
PrimitivesTest primitivesTest = new PrimitivesTest();

primitivesTest.randomIntFinder(scanner);
primitivesTest.doubleAddingCalculator(scanner);
primitivesTest.getRomanNumerals (scanner);

scanner.close();

Enter 2 numbers and get a random integer between those two numbers!
Enter the first integer: Enter the next integer: Random number between 1 and 10: 6

Enter 2 decimals to get their sum!
Enter the first double: Enter the next double: Sum: 3.300000

Enter any number: Roman numeral: XVII