[Java] 난수 - 두 수 사이의 난수 생성 & 로또 숫자 생성

1. 두 수 사이의 난수

 

프로그램 사용자로부터 최대 정수 A와 최소 정수 B를 입력 받는다. 그리고 A와 B사이에 존재하는(A와 B도 포함) 난수 10개를 생성해서 출력하는 프로그램을 작성해보자.

 

import java.util.Arrays;
import java.util.Random;
 
class Lotto
{
    private int[] lotto;
    private Random random;
    private final int MAX = 6;
 
    Lotto()
    {
        lotto = new int[MAX];
        random = new Random();
    }
    public void execute()
    {
        makeLotto();
        sortLotto();
        printLotto();
    }
    public boolean chkNum(int idx)
    {
        for(int i=0; i<idx; i++)
        {
            if(lotto[idx] == lotto[i])
            {
                return false;
            }
        }
        return true;
    }
    public void makeLotto()
    {
        for(int i=0; i<lotto.length; i++)
        {
            lotto[i] = random.nextInt(45)+1;
            if( !chkNum(i))
            {
                i--;
            }
        }
    }
    public void sortLotto()
    {
        Arrays.sort(lotto);
    }
    public void printLotto()
    {
        System.out.println(Arrays.toString(lotto));
    }
}
class LottoMain
{
    public static void main(String[] args)
    {
        Lotto lotto = new Lotto();
        for(int i=0; i<5; i++)
            lotto.execute();
    }
}

 

 

- 1차원 배열 버전

import java.util.Arrays;
import java.util.Random;
 
class Lotto
{
    private int[] lotto;
    private int[] number;
    private Random random;
    private final int MAX = 6;
    private final int RANGE = 45;
    
    Lotto()
    {
        number = new int[RANGE];
        lotto = new int[MAX];
        random = new Random();
        for(int i=0;i<number.length;i++)
            number[i] = i+1;
    }
    public void execute()
    {
        shuffle();
        sortLotto();
        printLotto();        
    }
    public void shuffle()
    {
        for(int i=0;i<RANGE;i++)
        {
            for(int j=0;j<10;j++)
            {
                int k = random.nextInt(45);
                int temp = 0;
                temp = number[i];
                number[i] = number[k];
                number[k]= temp;
            }
        }
        System.arraycopy(number, 0, lotto, 0, MAX);
    }    
    public void sortLotto()
    {
        Arrays.sort(lotto);
    }
    public void printLotto()
    {
        System.out.println(Arrays.toString(lotto));
    }
}
    
class LottoMain2
{
    public static void main(String[] args)
    {    
        Lotto lotto = new Lotto();
        for(int i=0;i<5;i++)
            lotto.execute();
    }
}

 

 

- 2차원 배열 버전

import java.util.Arrays;
import java.util.Random;
 
class Lotto
{
    private int[][] lotto;
    private Random random;
    private final int MAX = 6;
    private int numOfLotto;
    
    Lotto(int numOfLotto)
    {
        this.numOfLotto = numOfLotto;
        lotto = new int[numOfLotto][MAX];
        random = new Random();
    }
    public void execute()
    {
        makeLottos();
        sortLottos();
        printLottos();        
    }
    public void makeLottos()
    {
        for(int i=0;i<numOfLotto;i++)
        {
            makeLotto(lotto[i]);
        }
    }
    public void sortLottos()
    {
        for(int i=0;i<numOfLotto;i++)
        {
            sortLotto(lotto[i]);
        }
    }
    public void printLottos()
    {
        for(int i=0;i<numOfLotto;i++)
        {
            printLotto(lotto[i]);
        }
    }    
    public boolean chkNum(int idx, int[] lotto)
    {
        for(int i=0;i<idx;i++)
        {            
            if(lotto[idx]==lotto[i])
            {
                return false;
            }
        }
        return true;
    }
 
    public void makeLotto(int[] lotto)
    {
        int tmp=0;
        for(int i=0;i<lotto.length;i++)
        {
            lotto[i] = random.nextInt(45)+1;
            if( !chkNum(i, lotto) )
            {
                i--;
            }
        }
    }
 
    public void sortLotto(int[] lotto)
    {
        Arrays.sort(lotto);
    }
 
    public void printLotto(int[] lotto)
    {
        System.out.println(Arrays.toString(lotto));
    }
}    
class LottoMain3
{
    public static void main(String[] args)
    {    
        Lotto lotto = new Lotto(5);
        lotto.execute();
    }
}