How do I find the palindrome of a number?

Question

I already wrote the part of the program that reverses the number:

        int n = 0;
        n = Convert.ToInt32(textBox1.Text);
        double l = n;
        double reverse = 0;
        while (left > 0)
        {
            double r = left % 10;
            reverse = reverse * 10 + r;
            l = l / 10;
        }

        double final = n + rev;

However, if the final double does is not a palindrome, I want the program to add the final to its palindrome, and keep doing that until the a palindrome is found. The problem is in the the conditional statement.What condition should I give to the if statement?

Don't use doubles, for one thing. Just stick to `int` since that's your input. — Blorgbeard, Aug 09 '13 at 01:02
I think [this](http://en.wikipedia.org/wiki/Palindromic_number#Lychrel_process) is what he's trying to do. — Michi, Aug 09 '13 at 01:24

zs2020 · Answer 1 · 2013-08-09T01:06:59.427

2

I think you can just reverse the string rather than treat it as a number:

using System.Linq;

var N = textBox1.Text;
var reversedN = new string(n.Reverse().ToArray());
var result = Convert.ToInt32(reversedN);

edited Aug 09 '13 at 01:06

answered Aug 09 '13 at 01:01

zs2020

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This is much better than my previous while loop. Very helpful. – lost_in_the_source Aug 09 '13 at 11:43

score 1 · Accepted Answer · edited May 23 '17 at 12:11

1

As in this thread

bool isPalindrome(String s)
{
    char[] charArray = s.ToCharArray();
    Array.Reverse( charArray );
    return s.equals(new string(charArray));
}

Do the palindrome check on the string. If it's not a palindrome, convert the string to an int, add whatever you want, convert it back to a string, repeat.

Avoid working with double in this application. Stick to int.

edited May 23 '17 at 12:11

Community

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answered Aug 09 '13 at 01:18

Michi

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How do I find the palindrome of a number?

2 Answers2