import java.util.*;

public class Main { static int i; public static void main(String[] args) { Scanner input = new Scanner(System.in); String s=""; while (true) { System.out.println("Input something to lexically analyze: "); s = input.nextLine(); analize(s); } }

public static void analize(String s)
{
    String t = "-1234567890_ abcdefjhijklmnopqrstuvwxyzABCDEFJHIJKLMNOPQRSTUVWXYZ";
    char[] tt = t.toCharArray();
    char[] cc = s.toCharArray();
    int z = 1,i = 0,j = 0; 
    for (i = 0; i < cc.length; i++)
    { 
        for (j = 0; j < tt.length; j++)
        { 
            if (cc[i] == tt[j])
            {
                System.out.println("Token " + z + " = '" + cc[i] + "'"); 
                z++;
                break;
            }
        }
        if (j > tt.length-1)
        {
            System.out.println("Invalid character " + (i + 1) + " ('" + cc[i] + "') entered...");
        }
    }
}

}