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Thread: [Solved] Palindrome

  1. #1
    Junior Member satyarlenka's Avatar
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    Question [Solved] Palindrome

    It has been a few weeks for me in Java. Yesterday I was trying to write a program to check if a given number is palindrome or not. I was able to write a program in which it asks the user to input the number of digits. It ran okay without any errors.
    public class PalindromeNumberCheck {
     
    	public static void main(String[] args) {
    		// TODO Auto-generated method stub
    		System.out.println("Enter the number to be checked : ");
    		Scanner input = new Scanner(System.in);
    		int num = input.nextInt();
    		int numOriginal = num;
    		System.out.println("Enter the number of digits : ");
    		int n = input.nextInt();
    		int reverse = 0;
    		while(n != 0) {
    			reverse = reverse + (num%10) * (int)Math.pow(10,(n-1));
    			num = num / 10 ;
    			n--;
    		}
    		System.out.println("reverse = "+reverse);
    		if(reverse == numOriginal)
    			System.out.println("The number is a palindrome !");
    		else
    			System.out.println("The number is not a palindrome !");
    	}
     
    }
    My question is, Is there any other way to do it without asking the user to input the number of digits? Kindly someone point out the logic and I will try out to write the program by myself.


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    Default Re: [HELP] Palindrome

    You mean you want to use the program's logic to figure out how many digits the user entered, right?

    There are a number of ways. The simplest that occurs to me is to first accept the number as a String using input.nextLine(), then use a String method to determine its length, then parse the String object to an integer using Integer.parseInt( inputString ).

    If there are elements of that suggestion you can't or won't use for whatever reason, then you could divide the number entered as an int by 10 in a loop until the value is < 10 and use a counter to determine how many digits it has.

    Will either of those suggestions work for you?

  3. The Following User Says Thank You to GregBrannon For This Useful Post:

    satyarlenka (October 14th, 2013)

  4. #3
    Junior Member satyarlenka's Avatar
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    Default Re: [HELP] Palindrome

    Thanks Greg!! Oh my god. That's easy. It never really stuck my mind. Especially the second one.(facepalm)

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