Sec-pass

Our code is for generating passwords ramdomly. For people who concern about their security and are tired of using the same passwords again and again, we can help those people to generate passwords with ramdom numbers and charaters which will greatly help them to protect their pravicy. In addition, they do not need to worry about do not remenber passwords since we will automacily save the password by default.

import java.util.; import java.io.; import java.text.*;

public class AnswerGener {

private static String currTime; //current time
private static int length;  //length of password
private static boolean isInt;   //check for integer type input
private static boolean needSpecial; //check for whether user need special characters

static Random rand = new Random();
//each character is randomly pick from this array
static String sLetter[] = {"a", "b", "c", "d", "e","f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z",
        "A", "B", "C", "D", "E","F", "H", "I", "J", "K", "L", "M", "N", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "X", "Z",
        "1", "2", "3", "4", "5", "6", "7", "8", "9", "0", "!", "@", "#", "$", "%", "^", "&", "*", "(", ")", "_", "+"};

private static void initialize(){
    currTime = "";
    length = 0;
    isInt = false;
    needSpecial = false;
}

public static void lenPassword(){
    Scanner input = new Scanner(System.in);
    do{
        System.out.println("Please enter the length of password: ");
        if (input.hasNextInt()){
            length = input.nextInt();
            if (length > 5 && length < 17) {
                isInt = true;
            }else{
                System.out.println("The length of password is not vaild!"
                        + " We recommend the length of password between 6 and 16.");
                isInt = false;
            }
        }else{
            System.out.println("Plase enter valid number!");
            isInt = false;
            input.next();
        }
    } while (!(isInt));

}

public static void specialChar(){
    String yes = "yes";
    String no = "no";
    boolean vaildInput;
    Scanner kbd = new Scanner(System.in);
    String putin;
    do {
        System.out.println("Do you need special character in your password (yes or no)?");
        if (kbd.hasNext()){
            putin = kbd.next();
            if(yes.equalsIgnoreCase(putin)){
                vaildInput = true;
                needSpecial = true;
            }else if(no.equalsIgnoreCase(putin)){
                vaildInput = true;
                needSpecial = false;
            }else{
                System.out.println("Your input is not vaild!");
                vaildInput = false;
            }
        }else{
            System.out.println("Your input is not vaild!");
            vaildInput = false;
        }
    } while (!(vaildInput));
}

public static ArrayList<String> password(String [] sLetter){
    ArrayList <String> iniPassword = new ArrayList <String>();  //iniPassword is the password in ArrayList form
    int passwordIndex = 0;  //passwordIndex will be randomly assigned new integer 
    if (needSpecial == true){   //password has special characters
        for (int i = 0; i < length; i++){
            passwordIndex = rand.nextInt(75);   //only randomly generate integers from 0 to 75
            iniPassword.add(sLetter[passwordIndex]);
        }
    }else{  //password hasn't special characters
        for (int i = 0; i < length; i++){
            passwordIndex = rand.nextInt(63);   //randomly generate integers from 0 to 63, last 12 elements in array sLetter are special characters
            iniPassword.add(sLetter[passwordIndex]);
        }
    }
    return iniPassword;
}

public static void writing(String password){
    //write password into Password.txt
    try{
        FileWriter fw = new FileWriter("Password.txt", true);   //new content will not cover previous content by declaring true
        BufferedWriter bw = new BufferedWriter(fw); //decorator
        bw.write(password);
        bw.close();
    }catch(IOException e){
        System.out.println("ERROR");
    }
}

public static void main(String[] args) {
    initialize();

    //get current date and time
    Date dt = new Date();   //dt is the current time
    DateFormat df = new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");    //set format for current time(dt)
    currTime = df.format(dt);   //use format() from DateForat to get certain format for current time

    lenPassword();
    specialChar();

    //convert arraylist to string
    String realpassword = password(sLetter).toString().replace(" ", "").replace(",", "").replace("[","").replace("]", "");  //convert to string from ArrayList format
    //finally write password into Password.txt
    writing(currTime + "\tPassword: " + realpassword + "\n");
}

}