CODEWITHSUNDEEP
javapalindrome
Noman Prodhan
Noman Prodhan

Reputation: 27

Java program to find palindrome numbers in given range

I am trying to find Palindrome numbers in a given range. Here is my code:

import java.util.Scanner;
import java.util.ArrayList;

public class PalindromeNums{
    public static void main(String [] args){
        Scanner input = new Scanner(System.in);
        int start,end,rem,rev=0,temp;
        ArrayList <Integer> palindrome = new ArrayList<>();
        System.out.print("Start : ");
        start = input.nextInt();
        System.out.print("End : ");
        end = input.nextInt();

        temp = start;
        for(int i = start; i <= end; i++){

            while(temp != 0){
                rem = temp % 10;
                rev = rev * 10 + rem;
                temp = temp / 10;
            }

            System.out.println(rev);
            if(i == rev){
                palindrome.add(i);
            }
            temp++;
            rev = 0;
        }
        System.out.println(palindrome);

    }
}

When I run the code, it's giving the right output for the first integer only. It's not working for other integers in the given range. Any suggestion/solution for this problem? And why it's not working?

Sample output:

Start : 33 End : 55 33 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 [33]

Upvotes: 0

Views: 6319

Answers (3)

Hari
Hari

Reputation: 11

Please try this

import java.util.Scanner;
import java.util.ArrayList;

public class PalindromeNums{
    public static void main(String [] args){
        Scanner input = new Scanner(System.in);
        int start,end,rem,rev=0,temp;
        ArrayList <Integer> palindrome = new ArrayList<>();
        System.out.print("Start : ");
        start = input.nextInt();
        System.out.print("End : ");
        end = input.nextInt();

     // Picking Each Number Of That Range;
        for(int i = start; i <= end; i++){
            temp =i;
            // Checking whether Its Palindrome Or Not
            while(temp != 0){
                rem = temp % 10;
                rev = rev * 10 + rem;
                temp = temp / 10;
            }

            System.out.println(rev);
            if(i == rev){
                palindrome.add(i);
            }
            rev = 0;
        }
        System.out.println(palindrome);

    }
}

Upvotes: 1

Thiyagu
Thiyagu

Reputation: 17900

By the time the loop ends, temp will be 0 and hence you should not be doing temp++.

Rather, you need to assign the current number being processed to temp as the first line of the for loop as

temp = i;

Upvotes: 0

Siddhesh Salgaonkar
Siddhesh Salgaonkar

Reputation: 163

Your temp is not incrementing by 1 in the loop.

// temp is initialized to start at first
while(temp != 0){
    rem = temp % 10;
    rev = rev * 10 + rem;
    temp = temp / 10;
}
// at the end of this temp's value is entirely changed.
// above temp is incremented here, ideally temp at the start should be incremented. You can do this by initializing temp as i
temp++;

Upvotes: 1

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