java loops, evens odds and zeros

Question

I am currently working on a program that counts the number of even, odds, and zeros in an user input number. I am having trouble with two things. One being I am not sure how to get the loop to continue until the sentinel number is entered, and the other is how do I count zeros as a zero and not an even number. Below is my code so far, Thank you in advance.

import java.util.Scanner;

public class CountDigitsWithSentinel
{
    
    public static void main(String[] args)
    {
      // Declare the identifiers
        final int SENTINEL = -99;
        int userInput;
        int oddNums = 0;
        int evenNums = 0;
        int numZeros = 0;
        // Declare the remaining identifiers ...

        Scanner scan = new Scanner(System.in);
        
        // Display the programmer's information
        
         
        
      System.out.println("Enter an integer value (-99 to end):");
       userInput = scan.nextInt();
        System.out.println("The number " + userInput + " contains");
        //Your code ...
       
        
        
         while (userInput > 0) {
            
            int rem = userInput % 10;
            
            
            if (rem% 2 == 0) {
               evenNums++;
            
         }
         
         else
         {
            oddNums++;
         }
            
            userInput = userInput / 10;
         }
        
        //Your code ...
        
        // Display the counts
      System.out.println("Zero digits: " + numZeros);
      System.out.println("Even digits: " + evenNums);
      System.out.println("Odd digits: " + oddNums);
        //Your code ...
         
        System.out.println("Have a nice day!");
    
}
}

Answer 1

You can add if(rem == 0) but I suggest you work with a string because if the number the user enters starts with 0, the program will not count it:

With int :

 public static void main(String[] args)
    {
      // Declare the identifiers
        final int SENTINEL = -99;
        int userInput,oddNums = 0,evenNums = 0,numZeros = 0;
        // Declare the remaining identifiers ...

        Scanner scan = new Scanner(System.in);
        
        // Display the programmer's information
        
         
        
      System.out.println("Enter an integer value (-99 to end):");
       userInput = scan.nextInt();
        System.out.println("The number " + userInput + " contains");
        //Your code ...
       
        
        
         while (userInput > 0) {
            
            int rem = userInput % 10;
            
            
            if (rem% 2 == 0) {
               evenNums++;
            
         }
         
         else
         {
            oddNums++;
         }
            if(rem == 0) {
                numZeros++;
            }
            
            userInput = userInput / 10;
         }
        
        //Your code ...
        
        // Display the counts
      System.out.println("Zero digits: " + numZeros);
      System.out.println("Even digits: " + evenNums);
      System.out.println("Odd digits: " + oddNums);
        //Your code ...
         
        System.out.println("Have a nice day!");
    
}
}

Output with int:

Enter an integer value (-99 to end):
054740102
The number 54740102 contains
Zero digits: 2
Even digits: 5
Odd digits: 3
Have a nice day!

With String :

public static void main(String[] args)
    {
      // Declare the identifiers
        final int SENTINEL = -99;
        String userInput = "";
        int oddNums = 0,evenNums = 0,numZeros = 0;
        // Declare the remaining identifiers ...

        Scanner scan = new Scanner(System.in);
        
        // Display the programmer's information
        
         
        
      System.out.println("Enter an integer value (-99 to end):");
       userInput = scan.nextLine();
        System.out.println("The number " + userInput + " contains");
        //Your code ...
       
        
        
         while (Integer.parseInt(userInput) > 0) {
            
            int rem = Integer.parseInt(userInput) % 10;
            
            
            if (rem% 2 == 0) {
               evenNums++;
            
         }
         
         else
         {
            oddNums++;
         }
            if(rem == 0) {
                numZeros++;
            }
            
            userInput = userInput.substring(0, userInput.length() - 1);
         }
        
        //Your code ...
        
        // Display the counts
      System.out.println("Zero digits: " + numZeros);
      System.out.println("Even digits: " + evenNums);
      System.out.println("Odd digits: " + oddNums);
        //Your code ...
         
        System.out.println("Have a nice day!");
    
}
}

Output with string:

Enter an integer value (-99 to end):
054740102
The number 054740102 contains
Zero digits: 2
Even digits: 5
Odd digits: 3
Have a nice day!

Answer 2

I would probably cast it to a string and then evaluate it with regular expressions in a switch statement. If you cache (predefine) the reg-exes this would also be rather efficient because it wouldnt be necessary to convert each char to an int first.