Member Avatar for RawrInYoMouth

//Hello(apologize for any formatting errors)
//I am trying to finish this program that is supposed to act as a club bouncer. Only letting a max amount of people (125) in at one time. Naturally people leave throughout the night, so I was trying to //implement that with the random variable, but it keeps producing negative values. Any help would be greatly appreciated.

import java.util.Random;
     import javax.swing.JOptionPane;

       public class Clubmanger
    {
       public static void main(String[] args)
       {
          int counter = 0;
            Random leaving=new Random();
        do
        {
            int addperson=Integer.parseInt(JOptionPane.showInputDialog("Welcome to Club G, how many people in your party?"));
            if(addperson+counter>125)
            {
                JOptionPane.showMessageDialog(null,"There are too many people inside the club to allow you entry, please try again later");
                System.exit(0);
            }
            else
            {
                counter=+addperson;
                JOptionPane.showMessageDialog(null,"There are currently: "+counter+" people inside.");
            }
            int personleaving=leaving.nextInt(counter)+1;
            counter=-personleaving;
            JOptionPane.showMessageDialog(null,"There are:"+counter+"inside the club.");

        }while(counter<=124);    
    }

    }
Edited by RawrInYoMouth
  • 3 Contributors
  • 3 Replies
  • 198 Views
  • 7 Hours Discussion Span
  • Latest Post Latest Post by IIM

Dani AI

Generated

Two small logic errors are causing the symptoms you see: the running total is being replaced instead of incremented, and the random leaving count isn’t constrained to the current occupancy. already pointed out that you shouldn’t negate the leaving value; was correct to call out the random bound. Fix both and the negative/out‑of‑range counts go away.

Key points to apply:

  • Always add a new party to the existing total (don’t overwrite the total).
  • Generate the number leaving with a bound based on the current occupancy. Remember that Random.nextInt(n) produces 0..n-1 and requires n>0; using nextInt(occupancy + 1) yields 0..occupancy safely.
  • Subtract the leaving count from the total (do the subtraction explicitly) and validate user input / handle cancelation so you never try nextInt(0).

A short, safe example (variable names changed from the original) that shows these ideas:

import java.util.Random;
import javax.swing.JOptionPane;

public class ClubBouncerExample {
    public static void main(String[] args) {
        final int MAX_CAP = 125;
        int occupancy = 0;
        Random rnd = new Random();

        while (true) {
            String s = JOptionPane.showInputDialog("How many in your party?");
            if (s == null) break; // user cancelled
            int group;
            try { group = Integer.parseInt(s.trim()); }
            catch (NumberFormatException ex) { JOptionPane.showMessageDialog(null, "Enter a number."); continue; }
            if (group <= 0) { JOptionPane.showMessageDialog(null, "Positive group size required."); continue; }
            if (occupancy + group > MAX_CAP) { JOptionPane.showMessageDialog(null, "Club full for now."); continue; }

            occupancy = occupancy + group; // add the party
            int leaving = rnd.nextInt(occupancy + 1); // 0..occupancy
            occupancy = occupancy - leaving; // remove those who left

            JOptionPane.showMessageDialog(null, "Now inside: " + occupancy);
        }
    }
}

Troubleshooting notes: guard against zero/negative input, handle cancel, and decide whether you want “0 allowed to leave” (realistic) or “at least one leaves” — if the latter, only compute a leave value when occupancy>0 and use a different bound.

Recommended Answers

All 3 Replies

Member Avatar for efxee

that is because tour random variable has values greater than your counter, try to limit your randomization to the counter

Member Avatar for RawrInYoMouth

but I want to limit it to only the values that the counter has. I don't want it to generate per say 80 if there are only 30 people inside

Member Avatar for IIM

No your random variable is giving correct value.The error is because of line 24

  counter=-personleaving;//you are makin the value negative here by taking negative of personleaving

I think so you want to subtract personleaving from counter.It should be:-

 counter-=personleaving; //subtract personleaving from counter.
Be a part of the DaniWeb community

We're a friendly, industry-focused community of developers, IT pros, digital marketers, and technology enthusiasts meeting, networking, learning, and sharing knowledge.