How do I show the entire calculation in the output?

Question

Good evening,

I'm a beginner in java and I was assigned to code a program to decompose prime number. This is what I've got so far.

package introductionProgramming;

import javax.swing.JOptionPane;

public class Primes {
                public static void main(String[] args) {
                int primo;

    primo = Integer.parseInt(JOptionPane.showInputDialog("Inform prime number: "));

        while (prime % 2 == 0) {
            prime = prime / 2;
        }
        while (prime % 3 == 0) {
            prime = prime / 3;
        }
        while (prime % 5 == 0) {
            prime = prime / 5;
        }

        JOptionPane.showMessageDialog(null, prime);
                }
    }

So the decomposition part seems to work but I need the output, if entered the number 180, to look similar to this:

I have no clue how to do it.

How about, in each of your `while` loops, before you do the division, you could print out the dividend and the divisor. Would that work for you? — Dawood ibn Kareem, May 26 '14 at 00:53
@DavidWallace Could you show how to do it? I'm new and really confused but I think it might work. :) — user3674747, May 26 '14 at 01:00
@KickButtowski Not really. It doesn't matter how I show the decomposition as long as I show it. — user3674747, May 26 '14 at 01:08
Are you actually asking me to write code to show you how to print values to your console? — Dawood ibn Kareem, May 26 '14 at 01:10
@DavidWallace well, I think so. As I said, I'm a beginner and I don't know a lot of simple things. I tried using system.out.print but I don't use it correctly. So far I've only used JOptionPane. — user3674747, May 26 '14 at 01:19
OK, if you don't know how to use `System.out.print` or anything similar, I suggest you start with an easier project than this one. Perhaps working your way through the online Java tutorials would be a good idea. — Dawood ibn Kareem, May 26 '14 at 01:20

Rami Del Toro · Answer 1 · 2014-05-26T02:08:29.590

1

To send the calcultation as a whole to the output, you will need to gather all results and send it as a whole. To achieve this, when finding each result, you will add the appropriate text to a StringBuffer object, that will gather the results where ultimately it will be displayed. Below is an example of your code.

public class Primes {
    public static void main(String[] args) {


    int prime = Integer.parseInt(JOptionPane.showInputDialog("Inform prime number: "));
    StringBuffer resultsBuffer = new StringBuffer();

    while (prime % 2 == 0) {
        resultsBuffer.append(prime+" "+2+"\n");
        prime = prime / 2;

    }
    while (prime % 3 == 0) {
        resultsBuffer.append(prime+" "+3+"\n");
        prime = prime / 3;

    }
    while (prime % 5 == 0) {
        resultsBuffer.append(prime+" "+5+"\n");
        prime = prime / 5;

    }

    resultsBuffer.append(prime+" "+1+"\n");



    JOptionPane.showMessageDialog(null, resultsBuffer);
    }
}

edited May 26 '14 at 02:08

answered May 26 '14 at 01:16

Rami Del Toro

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did you even run this code to see the outcome of your code? – Kick Buttowski May 26 '14 at 01:37
Yes, it shows all the results, but now noticed the OP also wants the divisor next to the result, editing the answer. – Rami Del Toro May 26 '14 at 01:42
1

Yeah, this doesn't do what the OP wanted. It also seems a bit pointless putting everything in a list to print afterwards, instead of just printing each time you divide. Lastly, if you insist on storing things in a list and iterating at the end, I would recommend using an enhanced for loop. – Dawood ibn Kareem May 26 '14 at 01:42
for love of God, can you come with good message that makes sense on the screen? so you can get voted up – Kick Buttowski May 26 '14 at 01:49
Yes, agree with you David. Updated the example. – Rami Del Toro May 26 '14 at 01:49
1

I don't think `resultsBuffer.append(prime+" "+1+"\n");` is in the right place. – Dawood ibn Kareem May 26 '14 at 01:57
Yes, you're right. Needed to be out of the while loop, thank you. – Rami Del Toro May 26 '14 at 02:09

How do I show the entire calculation in the output?

1 Answers1