LetterFinder.java

import javax.swing.JOptionPane;

public class LetterFinder
{
    private static int numberTry, sizeMax = 21, tab;
    private static char [] [] tabTry;
    private static char[] similar;
    private static boolean end = false;

    public static void main(String[] args)
    {
        init(0);
        while(true)
        {
            tabTry [tab] = writeCharTab(enter(JOptionPane.showInputDialog("Entrez les lettres (série " + numberTry + ")(" + (sizeMax-1) + " caractères max):")));
            if(numberTry >= 3)
            {
                similar = finder(tabTry[0], tabTry[1]);
                while(!end)
                {
                    try
                    {
                        init(Integer.parseInt(JOptionPane.showInputDialog(endSentence())));
                    }
                    catch (java.lang.NumberFormatException e1)
                    {
                        end = false;
                    }
                    catch (java.lang.NullPointerException e1)
                    {
                        System.exit(0);
                    }
                }
            }
        }
    }

    private static char[] writeCharTab(String entered)
    {
        int posWrite = 0;
        char[] charTab = new char [sizeMax];
        for(int i = 0; i < entered.length(); i++)
        {
            charTab[posWrite] = entered.charAt(i);
            posWrite++;
        }
        tab++;
        numberTry++;
        return charTab;
    }

    public static String enter (String entered)
    {
        if (entered.length() > (sizeMax-1))
        {
            return "";
        }
        else
        {
            entered.toLowerCase();
            return entered;
        }
    }

    public static void init (int i)
    {
        if (i==0 || i==1)
        {
            tabTry = new char [2] [sizeMax];
            similar = new char [sizeMax];
            numberTry = 1;
            tab = 0;
            end = true;
        }
        else if (i==1)
        {
            tabTry = new char [2] [sizeMax];
            for (int i2 = 0; i2 < similar.length-1; i2++)
            {
                tabTry [0] [i2] = similar[i2];
            }
            similar = new char [sizeMax];
            tab = 1;
            end = true;
        }
        else if(i==3)
        {
            System.exit(0);
        }
    }

    public static char[] finder (char[] tab1, char[] tab2)
    {
        int posWrite = 0;
        char[] same = new char [sizeMax];
        for(int i = 0; i < (tab1.length); i++)
        {
            for(int j = 0; j < (tab2.length); j++)
            {
                if(tab1[i] == tab2[j])
                {
                    if(!(tab1[i] == ' ' || tab2[j] == ' '))
                    {
                        same[posWrite] = tab1[i];
                        tab1[i] = ' ';
                        tab2[j] = ' ';
                        if(posWrite < same.length-1)
                            posWrite++;
                    }
                }
            }
        }
        return same;
    }

    public static String endSentence ()
    {
        String s;
        try
        {
            s = "";
            for (int i = 0; i < similar.length-1; i++)
            {
                String s1 = (similar[i] + " ").toUpperCase();
                s = s + s1;
            }
        }
        catch (java.lang.NumberFormatException e1)
        {
            s = "erreur";
        }
        return "Les lettres en commun sont:\n " + s + "\n\n1. Entrer une autre série\n2. Recommencer\n\n3. Quitter";
    }

}