Thread: lucky draw.. (pls help)

thanks

Hello amin,

Welcome to the Java Programming Forums.

There is no code attached?

Is there a lot of code? If there isn't that much, please post your code within the code tags. (check my sig)

1st question: are you allowed to create other classes? That would make this task a lot easier.

public class Contestant
{
     String id;
     String name;
     String phoneNo;
     String email;
     String address;
     int drawNumber;
 
     public Contestant(String id, String name, String phoneNo, String email, String address, int drawNumber)
     {
          this.id = id;
          this.name = name;
          this.phoneNo = phoneNo;
          this.email = email;
          this.address = address;
          this.drawNumber = drawNumber;
     }
 
     public void printOutInfo()
     {
          System.out.println("ID: " + this.id);
          System.out.println("Name: " + this.name);
          System.out.println("phone number: " + phoneNo);
          System.out.println("email: " + email);
          System.out.println("address: " + address);
          System.out.println("draw number: " + drawNumber);
     }
 
     public int getDrawNumber()
     {
          return this.drawNumber();
     }
 
 
     public String getName()
     {
          return this.name();
     }
}

Then, in your main class create an array of Contestants. There are 2 options for generating random numbers: the Random class, or using Math.random(). Personally, I prefer using Math.random(), but here i'll show you the Random class because it should be easier.

Random generator = new Random();
generator.nextInt(upperLimit);

I'm not sure what the range on the draw number are, but just plug that into the upperLimit.

Then to find your winner, just loop through all the contestants, looking for a contestant that has a matching drawNumber using the getDrawNumber method I had above.

1. done > user enter the registration of participation (ID, full name, telephone number, email address, lucky draw number)

2. done > user the number of winning numbers.

3. done > generate random number from within the specified range

4. done > display the winning number and the winner’s name.

5. not done > generate random number until all the winning numbers are generated. and the generated number must match with the participant lucky draw number.

help me with this..

import java.util.*;
import java.io.*;
 
public class luck
{
	public static void main(String[] args)
		{
		Scanner input = new Scanner(System.in);
 
		System.out.println(" ");
		System.out.println("-------------------------- WELCOME TO LUCKYDRAW EVENT --------------------------");
		System.out.println(" ");
		System.out.print("Please enter number of participants for lucky draw event: ");
		int numberOfParticipants = input.nextInt();
		System.out.print("Please enter number of winners for lucky draw event: ");
		int numberOfWinners = input.nextInt();
		System.out.println("");
 
		String[] luckyDrawId = new String[numberOfParticipants];
		String[] luckyDrawName = new String[numberOfParticipants];
		int[] luckyDrawPhoneNo = new int[numberOfParticipants];
		String[] luckyDrawEmail = new String[numberOfParticipants];
		String[] luckyDrawAddress = new String[numberOfParticipants];
		int[] luckyDrawNumber = new int[numberOfParticipants];
		String information = " ";
 
		System.out.println("-------------------------- PARTICIPANT REGISTRATION ---------------------------");
 
		for (int i = 0; i < luckyDrawNumber.length; i++)
			{
			/*System.out.println(" ");
			System.out.print("Please enter lucky draw number's Id: ");
			luckyDrawId[i] = input.next();*/
			System.out.print("Please enter lucky draw number's name: ");
			luckyDrawName[i] = input.next();
			/*System.out.print("Please enter lucky draw number's Phone No: ");
			luckyDrawPhoneNo[i] = input.nextInt();
			System.out.print("Please enter lucky draw number's Email: ");
			luckyDrawEmail[i] = input.next();
			System.out.print("Please enter lucky draw number's Address: ");
			luckyDrawAddress[i] = input.next();*/
			System.out.print("Please enter lucky draw's number: ");
			luckyDrawNumber[i] = input.nextInt();
			System.out.println(" ");
			}
 
		System.out.println(" ");
		System.out.println("---------------------- RANGE OF GENERATING RANDOM NUMBER ----------------------- ");
 
		System.out.print("enter maximum number for generating random number: ");		
		int max = input.nextInt();
 
		int[] winningNum = new int[numberOfWinners];
		for(int i=0;i<numberOfWinners;++i)
			{
			winningNum[i] = (int) (Math.random()*max);
			for(int j=0;j<i;++j)
				{
				if(winningNum[i] == winningNum[j])
				++i;
				}
			}
		for (int i = 0; i < winningNum.length; i++)
			{
			if (winningNum[i] == luckyDrawNumber[i])
				{
				System.out.println("congratulations!! the winner is " + luckyDrawName[i] );
				System.out.println("congratulations!! the random lucky number is " + winningNum[i] );
 
				}
			else 
				{
				System.out.println("our random number is " + winningNum[i] + " does not match with any participant lucky draw number " +luckyDrawNumber[i]);
				}
			}
		}
}

my time is ticking

Please don't make multiple posts with the same question...

Since you said you're not allowed to use other objects, use a for loop:

for (int i = 0; i < id.length;i++)
{
    System.out.println("ID: " + id[i]);
          System.out.println("Name: " + name[i]);
          System.out.println("phone number: " + phoneNo[i]);
          System.out.println("email: " + email[i]);
          System.out.println("address: " + address[i]);
          System.out.println("draw number: " + drawNumber[i]);
}

To find a matching draw number:

int matchIndex = 0;
for (int i = 0; i < drawNumber.length; i++)
{
     if (drawNumber[i] == numberToMatchTo)
     {
          matchIndex = i;
          break;
     }
}
// matchIndex contains the index to the info of the winner

You have to compare each random number with every contestant.

for (int i = 0; i < winningNum.length; i++)
{
	for (int j = 0; j < luckyDrawNumber.length; j++)
	{
		if (winningNum[i] == luckyDrawNumber[i])
		{
			System.out.println("congratulations!! luckyDrawName[i] + " has one with a luckyDraw number of " + winningNum[i]);
		}
	}
}

Hmm, well instead of generating luck-draw numbers, you can generate random indices, and add that to the list of winners. Then you just need to make sure you don't pick the same person to be the winner multiple times. This is kind of like making the computer shuffle the deck: instead of shuffling all the cards and picking from the top, simply have the computer draw out a random card.