Not Sure where is the problem.

Question about the task

Even and odd digits

Java Syntax, Level 6, Lesson 5

Under discussion

Please can anyone tell me where is my issue is? Thanks ahead.

Use the keyboard to enter a positive number. Determine the number of even digits and odd digits in the entered number.
If a number is divisible by 2 without a remainder (i.e. the remainder is zero), then it is even.
And we'll increase the even digit counter (static variable even) by 1.
Otherwise, the number is odd, so we'll increase the odd digit counter (static variable odd).
Display the following message: "Even: a Odd: b", where a is the number of even digits and b is the number of odd digits.

Example for 4445:
Even: 3 Odd: 1

Requirements:

The program must read data from the keyboard.
The main method should calculate how many even digits are in the entered number and then write this number to the variable even.
The main method should calculate how many odd digits are in the entered number and then write this number to the variable odd.
The program should display text on the screen.
The displayed text must match the task conditions.

package com.codegym.task.task06.task0606; import java.io.*; /* Even and odd digits */ public class Solution { public static int even; public static int odd; public static void main(String[] args) throws IOException { //write your code here BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); int num = Integer.parseInt(reader.readLine()); while(num > 1){ if(num % 2 == 0){ even++; num /=10; } else{ odd++; num /= 10; } } int a = even; int b = odd; System.out.println("Even: "+a+" Odd: "+b); }}

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Michael Brimage

Level 19 , Washington D.C., United States

27 February 2020, 18:06

Why do you divide the number by ten?

Guadalupe Gagnon

Level 37 , Tampa, United States

27 February 2020, 18:19

Because it truncates the first number off. Integer division is not able to carry decimal values. Take for example 341, if you divide this number by 10 you would expect to end up with 34.1, however if both 341 and 10 are integers you will end up with 34. This code uses that quirk in the way the computer divides to remove the right most digit after it figures out if it is even or odd.

Michael Brimage

Level 19 , Washington D.C., United States

27 February 2020, 18:40

Guadalupe thanks. I still don't understand how this helps determine if individual integers in the larger integer is even or odd. what am I missing?

Guadalupe Gagnon

Level 37 , Tampa, United States

27 February 2020, 19:34

Using 341 as an example: line 20: loop that continues as long as the number is greater than 1 { line 21: checks if the number is even or odd next line: increases "even" or "odd" next line: truncates the right most digit } so: 341 mod 2 equals 0? --> this would be false so odd gets increased by 1 number = 341 divided by 10 --> this makes number equal to 34 34 mod 2 equals 0? --> this is true so even gets increased by 1 number = 34 divided by 10 --> this makes number equal to 3 3 mod 2 equals 0? --> this false so odd is increased by 1 number = 3 divided by 10 --> this makes number equal to 0 loop exits because number is no longer equal to 1 The output would be: "Even: 1 Odd: 2"

Michael Brimage

Level 19 , Washington D.C., United States

28 February 2020, 14:22

ahh i have it!! So, num /= 10 truncates and then the new number goes back into the loop. now that makes sense!! Thanks!

Tara Rosenthal

Level 18 , Farmers Branch, United States

26 February 2020, 20:43

I think the while loop should be num >= 1. Otherwise it will not calculate for the final digit if it is a 1. Or maybe make a special case for the last digit being a one if that doesn't work.