wont print zero

[jjth39347]

Okay this is trying to do the reverse number but when a zero in enter in the number it wont show up in the answer.

import java.util.Scanner;


public class Lab8
{

		public static void main(String[] args)
		{

			//original number
			long number;
			long reversedNumber = 0;
			long temp = 0;

	 		//import scanner
			Scanner keyboard = new Scanner(System.in);
			System.out.println("Enter a starting number");
			number = keyboard.nextInt();




			while(number > 0)
			{
				//use modulus operator to strip off the last digit
				temp = number%10;

				//create the reversed number
				reversedNumber = reversedNumber * 10 + temp;

				number = number/10;


			}

			//output the reversed number
			System.out.println("Reversed Number is: " + reversedNumber);

		}
}

[Iron Lion]

Ints don't have leading zeroes. You'll have to get a string from your scanner and reverse that.

Also, please use [code][/code] tags.

[sunde887]

Yes, it would also be much easier to get a string and loop through to reverse it.

[jjth39347]

sorry, I can switch it to a string but I have no idea how to use the operators I want on the string for it to still work.

[Iron Lion]

You don't need any division or modulus operations. All you need is a for loop and the charAt() method of String (and possibly some way of validating that the user is only entering numbers).

[jjth39347]

I also need to add an if else statement that states if the start number and the reverse number are the same or not.... ie

start: 1331
Reverse: 1331
The numbers are the same

Start 1234
Reverse 4321
The numbers are not the same.

[UJJAL DHAR]

Take an string from keyboard.Then reversed it and keep the reversed it in a new string type variable.Then compare it with first one.

[jjth39347]

would you mind dumbing that down a bit or a pseudo code?

[JosAH]

would you mind dumbing that down a bit or a pseudo code?

Sure, here's some real code:

private String reverse(String input) {
   return new StringBuilder(input).reverse().toString();
}
private boolean isPalindrome(String input) {
   return input.equals(reverse(input);
}

The code assumes that input isn't null and you still have to check whether or not its value forms a valid int value.

kind regards,

Jos

[UJJAL DHAR]

Did you see any tutorials or books? Its a simple one.

Scanner as=new Scanner(System.in);
String S=as.nextLine();

int i;
String b;

b="";

for(i=S.length()-1;i>=0;i--){
b+=S.charAt(i);
}

if(S.equals(b)){
System.out.println("Same");
}
else
System.out.println("No");

If you are satisfied,don't forget to press REP for me

[jjth39347]

Sure, here's some real code:

private String reverse(String input) {
   return new StringBuilder(input).reverse().toString();
}
private boolean isPalindrome(String input) {
   return input.equals(reverse(input);
}

The code assumes that input isn't null and you still have to check whether or not its value forms a valid int value.

kind regards,

Jos

we aren't allowed to make our own methods at this point in the class, I understand your code and like it just my teacher wont accept it.

[jjth39347]

my program does reverse it as an inturgral number but I can't figure out how to get it to print out a damn zero such as
type in 1023
it outputs 321

[jjth39347]

okay I caved and used string, my teacher can just get over it. It is the best way to solve this problem imo.
Thank you all, and thank you UJJAL DHAR.

[pbrockway2]

okay I caved and used string, my teacher can just get over it. It is the best way to solve this problem imo.

I agree with your humble opinion. "Reversing" an integral value sounds like a string operation and indeed it is: what is being reversed is the (or rather a) string representation of the value. While it's true that you can do the reversing with mathematical operators - because of the relationship between the digits used in the decimal form of the value and the first 10 whole numbers - it makes no sense to do so when the StringBuilder class exists.

What you were asked to do is akin to opening a bottle of wine with a screwdriver. Possible, but who would bother if they had a corkscrew?

Your teacher should have said how the leading zeros should be handled. Your code reverses 120 as 21 - if the teacher wanted leading zeros he or she should have said.

As I said above you can do this with numeric operations. Basically inside the while loop you count the number of times temp is zero before a nonzero value is obtained. Then, at the end, you print that many zeros before printing the value you have calculated.

This will handle trailing zeros in the input. You might like to ask your teacher sweetly about leading zeros in the user input. If the user enters 00666 the line

number = keyboard.nextInt();

will set the value of number to 666. getInt() effectively removes leading zeros and you have no way of telling how many there might have been. The only solution - and you want your teacher to admit this - is to read the user input as ... a string!

[jjth39347]

yea, she is constantly looking up questions that her students ask her because she doesn't really teach java. Hell she even ask me to answer the other students questions.

but here is the final code

import java.util.Scanner;


public class Lab8
{

	public static void main(String[] args)
	{
		Scanner keyboard=new Scanner(System.in);
		System.out.println("Please enter a number:");
		String number=keyboard.nextLine();

		int temp;
		String reverseNum;

		reverseNum="";
		temp=number.length()-1;
		while(temp>=0)
		{

			reverseNum+=number.charAt(temp);
			temp--;
		}
		System.out.println("The reverse number is:"+ reverseNum);
		if(number.equals(reverseNum))
		{
			System.out.println("The given number and reversed number are same.");
		}
		else
			System.out.println("The given number and reversed number are not same.");
	}
}

[pbrockway2]

It's your own understanding and learning. So long as you know what / and % can do and can intelligently defend not using them here, that's the main thing.

[jjth39347]

I wish I could "like" your comment pbrockway, cause its defiantly true.