Java program not outputting negative integers from array?

Question

One of my Java assignments is to take numbers from a file and then seperate them to two arrays. One named P (positive numbers) and N (negative numbers.) I have it working for the positive numbers but the negative numbers keep outputting 0s. I have no idea why! Help?

import java.io.*;
import java.util.*;

public class Prog404a {
    public static void main(String[] args) {
        Scanner inFile = null;
        try {
            inFile = new Scanner(new File("prg404a1.dat"));
        } catch (FileNotFoundException e) {
            System.out.println("File not found!!");
            System.exit(0);
        }
        int temp = 0;
        int P[] = new int[23];
        int N[] = new int[23];
        int i = 0;
        while (inFile.hasNext()) {
            temp = inFile.nextInt();
            if (temp < 0) {
                N[i] = temp;
            }
            if (temp > 0) {
                P[i] = temp;
            }
            i++;
        }
        for (int x = 0; x < i; x++) {
            System.out.println(P[x] + "\t" + N[x]);
        }
    }
}

EDIT: Never mind it's not working for positive numbers either. Only a few.

You are using the same index for both N and P, so if you have seen 3 positive integers, for example, before the first negative integer, it will be inserted at N[3]. Is that really what you want? — Code-Apprentice
– Code-Apprentice, Commented Feb 16, 2013 at 23:47
I strongly suggest that you learn how to debug your code. You can do this with the debugger in your IDE or add lots of System.out.println() calls to your code to see what is happening. — Code-Apprentice
– Code-Apprentice, Commented Feb 16, 2013 at 23:48

Has QUIT--Anony-Mousse · Accepted Answer · 2013-02-16 23:47:33Z

4

Maybe you are just not counting right?

You should be using two counters, one for positive, one for negative numbers. Otherwise, half of the entries will obviously be 0, because they were never set.

answered Feb 16, 2013 at 23:47

Has QUIT--Anony-Mousse

77.8k14 gold badges146 silver badges198 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

Andrew Martin Over a year ago

To elaborate further in case the OP doesn't realise, let's saying you are inputting these numbers [1, 3, -4]. P[0] = 1, P[1] = 3, N[2] = -4 (thus leaving N[0] and N[1] with no values).

Garrett Outlaw Over a year ago

Oh my God I get it now! I didn't realise it was raising the counter and the other array wasn't getting a number for that count. I fixed it and it works. Thank you. :)

Collectives™ on Stack Overflow

Java program not outputting negative integers from array?

1 Answer 1

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related