password

import java.util.*;

public class password
{

    public password()
    {

        Scanner sc = new Scanner(System.in);
        boolean playing = true;
        System.out.println("Welcome to the password checker!");
        while(playing){
            String pass = "";
            System.out.println("How long do you want your password to be?");
            int count = sc.nextInt();
            if(count < 4){
                System.out.println("Must be at least 4 characters.");
                count = sc.nextInt();
            }

            while(!checkPass(pass)){
                pass = "";
                for(int i = 0; i < count; i++){
                    pass = pass + randomChar();
                }
            }
            System.out.println(pass);
            System.out.println("Keep Going? ('Y' or 'N')");
            String cont = sc.next();
            if(cont.equals("N"))
                playing = false;
        }

    }
    public int randomNumber(int min, int max){
        int rnd =(int)(Math.random() * ((max - min) )) + min;
        return rnd;
    }

    public String randomChar()
    {
        String letters = "abcdefghijklmnopqrstuvwxyz";
        String chars = "abcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*?" + letters.toUpperCase();

        return String.valueOf(chars.charAt(randomNumber(0,chars.length()-1)));
    }

    public boolean checkPass(String pass){
        boolean lowercase = false;
        boolean uppercase = false;
        boolean hassymbol = false;
        boolean hasnum = false;

        String lower = "abcdefghijklmnopqrstuvwxyz";
        String upper = lower.toUpperCase();
        String nums = "0123456789";
        String symbols = "!@#$%^&*?";

        for(int i = 0; i < pass.length(); i++){
            String testing = String.valueOf(pass.charAt(i));
            if(lower.contains(testing))
                lowercase = true;
            if(upper.contains(testing))
                uppercase = true;
            if(nums.contains(testing))
                hasnum = true;
            if(symbols.contains(testing))
                hassymbol = true;   
        }

        return (lowercase && uppercase && hassymbol && hasnum);
    }
}