CODEWITHSUNDEEP
java
polaris
polaris

Reputation: 339

How to add leading zeros to an int?

If I input an int value, is it possible to keep a leading zero. For example if I input 0123, is there a way to pass that zero without formatting the data. I came across an exercise on a website which asks to enter an isbn number as an int and validate it. The initial code given is the following.

import java.util.Scanner;

public class isbncheck {

    public static void main(String[] args) { 
        int num= 0;
        int digit = 0;
        int sum = 0;

        System.out.println("Enter ISBN Number:");
        Scanner sc = new Scanner(System.in);

        num = sc.nextInt();

        /*
        Your code here
        */

        System.out.println("The ISBN number is:");
    }
}

the link to the website is http://www.programmr.com/challenges/isbn-validation-1

If I wanted to take the first digit of an input and do something with it, I cannot if the first integer is a 0. To test the code the input is 0201314525. However I lose the initial zero and then I cannot make the code work. I used a String input instead of an int which I can then manipulate to do what I want. Is it possible to complete the code given the way it's being presented?

Upvotes: 1

Views: 7229

Answers (2)

Elliott Frisch
Elliott Frisch

Reputation: 201537

No. int cannot be inherently formated, you could store it as a String. Or you will need to String#format() the int to have leading zeros,

String isbn = String.format("%013d", num); // 0 fill to 13 digits num

Upvotes: 0

Steve B.
Steve B.

Reputation: 57333

You will need to preserve the value as a String. You should do this anyway with something like an ISBN number since its value is not its magnitude but its string representation.

Why not just use " String num = sc.next(); " ?

Upvotes: 1

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