Java, How do I drop one single digit from a number (In order to perform a calculation on the rest of the number)?

Question

I am trying to figure out part of a Java assignment and I am lost on what to do. If anyone can help or guide me in the right direction I would really appreciate it!

The user has to enter a six digit "ticket number". I am trying to figure out how to drop the last digit of the number that the user input and place it into it's own variable.

For instance:

Ticket Number: 123456

How do I drop the "6" to make the number "12345" and put the 6 in its own variable?

I tried using the \\b to backspace the last digit after turning the input into a string, but that did not work. And I have realized that it would just delete the number anyway if it did work.

Once the last digit is dropped we have to do calculations to get a remainder... I'm not worried about that, I have found that described in our book, I just can't figure out how to drop the digit and put it by itself.

I am very new to Java (this is a Chapter 2 assignment) so please go easy on me!

Thank you everyone for your help. I appreciate it!

This is what I came up with and the code works:

import javax.swing.JOptionPane;

public class TicketNumber
{
    public static void main(String[] args)
    {
        String ticketNumber;
        int Ticket, Remainder, lastDigit;

        ticketNumber = JOptionPane.showInputDialog(null, 
            "Enter the six digit ticket number",
            "Verify Ticket", JOptionPane.INFORMATION_MESSAGE);

        Ticket = Integer.parseInt(ticketNumber) / 10;
        lastDigit = Integer.parseInt(ticketNumber) % 10;
        Remainder = Ticket % 7;
        boolean Valid = lastDigit == Remainder;

        JOptionPane.showMessageDialog(null, "Valid Ticket" + "\n" + Valid);
    }
}

Answer 1

It depends on what data type you are working with. If the value is a String , you can use the substring method:

String ticket = "123456";
String allButLast = ticket.substring(0, ticket.length() - 1); // becomes "12345"

If it is an int value, you can use integer division:

int ticket = 123456;
int allButLast = ticket / 10; // truncates to 12345

If it's a float or double , you can divide by 10 and cast to an int or you can use Math.floor() to drop the fractional part after dividing by 10.

EDIT: Based on the edit to your question, you can do this:

public class TicketNumber
{
    public static void main(String[] args)
    {
        String ticketNumber;
        int ticket, prefix, remainder, lastDigit;

        ticketNumber = JOptionPane.showInputDialog(null, 
            "Enter the six digit ticket number",
            "Verify Ticket", JOptionPane.INFORMATION_MESSAGE);

        ticket = Integer.parseInt(ticketNumber);
        prefix = ticket / 10;
        lastDigit = ticket % 10;
        remainder = prefix % 7;
        boolean valid = lastDigit == remainder;

        JOptionPane.showMessageDialog(null, "Valid Ticket" + "\n" + valid);
    }
}

Note that Ticket , etc. are not good Java variable names; they should start with lower-case letters (eg, ticket ). I made that change in my version of the code.

Note that the calculation can be written more tersely as:

boolean valid = (ticket % 10) == ((ticket / 10) % 7);

and you can eliminate the variables prefix , remainder , and lastDigit .

Answer 2

You can use modulo operator % and division operator /

int number = 123456;
int remainder = 123456 % 10;
int newNumber = 123456 / 10;
System.out.println(newNumber); // output is 12345
System.out.println(remainder); // output is 6

Answer 3

 int n=123456,m=n/10;
     System.out.println("Number = "+m);//your code

Your Output:-

Number = 12345