Thread: Problem with my simple pw verifier

Hello,

I am working on a password verifier that checks the characters to meet a certain criteria. The user enters in the number of passwords they need to check and then prompts them to enter each one. My for loop counter for each password is off. I am also having trouble with the word/# "null" and "0" appearing in the println when I run the program.

I need the user to be able to put in a password, then be prompted with a black space for the next password they need to enter. My code for the loop is as follows:
public void inputPassword () {
for (int i = 0; i < (passwordCount); i++) {
System.out.println(" Please enter each password: " + password);
password = keyboard.nextLine;

}
}
I know that the result of this is just adding the previous password onto the next line like "cat" then the next password will be "cat" + the next password entered and so on, im not sure how to correct this and get the loop to just take in a new password each time.


Then, like I said above when typing out a simple println like:

System.out.println( "Please enter your name:" + name);

the output is placing the word "null" right after the colon.

I apologize if this wasn't written in the correct format, but thank you for any assistance, my professor is very indirect with her "help".

Please follow along with the program to verify your passwords.
I am using a Scanner for the program.

Please enter your name: nulls ("null" appears for some reason)
Please enther the number of passwords you need to check: 013 (0 appears for no reason)
Please enter each password: nulldogI12 ("null appears for the first pw entry)
Please enter each password: dogI12cat123
Please enter each password: cat123cowT687
Please enter each password: cowT687

import java.util.Scanner;
   import java.io.*;
 
   public class PasswordChecker {
 
      private String password; 
      private String testPlanAuthor; 
      private String reportString;
      private int passwordCount, totalPasswords;
      private boolean lengthOK, lowercaseOK, uppercaseOK, digitOK;
      private final int MINIMUM_LENGTH = 6;
      PrintWriter outputFile;
      Scanner keyboard = new Scanner(System.in);
 
 
      public static void main (String[] args) throws IOException{
 
      // call methods
         PasswordChecker newInput = new PasswordChecker();
         newInput.startPasswordChecker();
         newInput.inputPassword();
         newInput.checkLength();
         newInput.checkLowerCase();
         newInput.checkUpperCase();
         newInput.reportValidity();
         newInput.printReport();
 
      } // End Main
 
   // start pwchecker
 
 
 
      public void startPasswordChecker() throws IOException {
 
 
         System.out.println("Welcome! " + " This is the Password Verification System." +
            							"\n Please follow along with the program to verify your passwords. ");
 
         System.out.print("Please enter your name: "+ (testPlanAuthor));
         testPlanAuthor = keyboard.nextLine();
 
 
         System.out.print("Please enther the number of passwords you need to check: "+ (passwordCount));
         passwordCount = keyboard.nextInt();
         keyboard.nextLine(); 
 
         outputFile = new PrintWriter("Passwordlist.txt");
      }
 
       // inputpassword
 
      public void inputPassword () {
 
 
         for (int i = 0; i < (passwordCount); i++) {
 
            System.out.print(" Please enter each password: " + (password));
            password = keyboard.nextLine();        
 
 
         }
 
      }

I did not post all of the code, i thought the problem might exist within that first half of the program since that was where I declared and initialized my variables.

--- Update ---

import java.util.Scanner;
   import java.io.*;
 
   public class PasswordChecker {
 
      private String password; 
      private String testPlanAuthor; 
      private String reportString;
      private int passwordCount, totalPasswords;
      private boolean lengthOK, lowercaseOK, uppercaseOK, digitOK;
      private final int MINIMUM_LENGTH = 6;
      PrintWriter outputFile;
      Scanner keyboard = new Scanner(System.in);
 
 
      public static void main (String[] args) throws IOException{
 
      // call methods
         PasswordChecker newInput = new PasswordChecker();
         newInput.startPasswordChecker();
         newInput.inputPassword();
         newInput.checkLength();
         newInput.checkLowerCase();
         newInput.checkUpperCase();
         newInput.reportValidity();
         newInput.printReport();
 
      } // End Main
 
   // start pwchecker
 
 
 
      public void startPasswordChecker() throws IOException {
 
 
         System.out.println("Welcome! " + " This is the Password Verification System." +
            							"\n Please follow along with the program to verify your passwords. ");
 
         System.out.print("Please enter your name: "+ (testPlanAuthor));
         testPlanAuthor = keyboard.nextLine();
 
 
         System.out.print("Please enther the number of passwords you need to check: "+ (passwordCount));
         passwordCount = keyboard.nextInt();
         keyboard.nextLine(); 
 
         outputFile = new PrintWriter("Passwordlist.txt");
      }
 
       // inputpassword
 
      public void inputPassword () {
 
 
         for (int i = 0; i < (passwordCount); i++) {
 
            System.out.print(" Please enter each password: " + (password));
            password += keyboard.nextLine();        
 
 
         }
 
      }
 
   // checklength
      public void checkLength () {
 
         lengthOK = false;
 
         if (password.length() >= MINIMUM_LENGTH) {	
 
            lengthOK = false;
 
         }
      }
   // checkLowerCase
      public void checkLowerCase() {
 
         lowercaseOK = false;
 
         int x = 0;
 
         while (x < password.length()){
 
            if (Character.isLowerCase(password.charAt(x))) {
 
               lowercaseOK= true;
 
               x++;         
            }
         }
      }
 
   // CheckUpperCase
      public void checkUpperCase() {
         int x = 0;	
         uppercaseOK = false;
 
         while ( x < password.length()) {
 
            if (Character.isUpperCase(password.charAt(x))) {
 
               uppercaseOK = true;
               x++;         
            }
         }
      }  
   // checkDigit
      public void checkDigit () {
 
         int x = 0;
         digitOK = false;
 
         while ( x < password.length()) {
 
            if (Character.isDigit(password.charAt(x))) {
 
               digitOK = true;
 
               x++;         
            }
         }
      }
   // reportValidity
      public void reportValidity () throws IOException {
 
 
         if (digitOK && lowercaseOK && uppercaseOK && lengthOK) {
 
            System.out.print(" The password is valid."); }
 
         if (lengthOK != true) {
            System.out.print(" The password is invalid. Its length must be at least 6 characters."); }
         if ( lowercaseOK != true) {
            System.out.print(" The password is invalid. There must be at least 1 lower case letter."); } 
         if (uppercaseOK != true) {
            System.out.print(" The password is invalid. There must be at least 1 upper case letter."); }
         if (digitOK != true) {
            System.out.print(" The password is invalid. There must be at least 1 digit."); }
 
      }
 
   // print Report
 
      public void printReport () throws IOException {
 
         if (digitOK && lowercaseOK && uppercaseOK && lengthOK) {
 
            outputFile.print("The password is valid."); }
 
         if (lengthOK != true) {
            outputFile.print(" The password is invalid. Its length must be at least 6 characters."); }	
         if ( lowercaseOK != true) {
            outputFile.print(" The password is invalid. There must be at least 1 lower case letter."); } 
         if (uppercaseOK != true) {
            outputFile.print(" The password is invalid. There must be at least 1 upper case letter."); }
         if (digitOK != true) {
            outputFile.print(" The password is invalid. There must be at least 1 digit."); }
 
         outputFile.close();
      } // end printreport  
 
   } // End PWChecker

Still fighting with it.
Im not sure I know where to use the nextLine() method to clear the buffer. Right after the nextInt? I fixed the strings with "" Im not sure I understand what I need to add in order to get the loop to stop printing the previous password.

no I just did password = keyboard.nextLine(); and it still concatenates

I dont want it to just add the previous pw im still just struggling with getting it to print out a new blank space in the scanner for the next password inside the for loop.

this portion below

public void inputPassword () {
 
 
         for (int i = 0; i < (passwordCount); i++) {
 
            System.out.print("Please enter each password: " + (password));
            password = keyboard.nextLine();        
 
 
         }
 
      }

this loop is causing the string to just append the previous one, it is replacing the password before it.
so pw #1 = cow
then pw2= cow+my next password lets say "dog"
then pw 3 = dog + the next password

 
   import java.util.Scanner;
   import java.io.*;
 
   public class PasswordChecker {
 
      private String password = " "; 
      private String testPlanAuthor = " "; 
      private String reportString;
      private int passwordCount; 
      private int totalPasswords;
      private boolean lengthOK, lowercaseOK, uppercaseOK, digitOK;
      private final int MINIMUM_LENGTH = 6;
      PrintWriter outputFile;
      Scanner keyboard = new Scanner(System.in);
 
 
      public static void main (String[] args) throws IOException{
 
      // call methods
         PasswordChecker newInput = new PasswordChecker();
         newInput.startPasswordChecker();
         newInput.inputPassword();
         newInput.checkLength();
         newInput.checkLowerCase();
         newInput.checkUpperCase();
         newInput.reportValidity();
         newInput.printReport();
 
      } // End Main
 
   // start pwchecker
 
 
 
      public void startPasswordChecker() throws IOException {
 
 
         System.out.println("Welcome! " + "This is the Password Verification System." +
            							     "\nPlease follow along with the program to verify your passwords. ");
 
         System.out.print("Please enter your name: "+ (testPlanAuthor));
         testPlanAuthor = keyboard.nextLine();
 
 
         System.out.print("Please enther the number of passwords you need to check: "+ (passwordCount));
         passwordCount = keyboard.nextInt();
         keyboard.nextLine();
 
 
      }
 
       // inputpassword
 
      public void inputPassword () {
 
 
         for (int i = 0; i < (passwordCount); i++) {
 
            System.out.print("Please enter each password: " + (password));
            password = keyboard.nextLine();        
 
 
         }
 
      }
 
   // checklength
      public void checkLength () {
 
         lengthOK = false;
 
         if (password.length() >= MINIMUM_LENGTH) {	
 
            lengthOK = false;
 
         }
      }
   // checkLowerCase
      public void checkLowerCase() {
 
         lowercaseOK = false;
 
         int x = 0;
 
         while (x < password.length()){
 
            if (Character.isLowerCase(password.charAt(x))) {
 
               lowercaseOK= true;
 
               x++;         
            }
         }
      }
 
   // CheckUpperCase
      public void checkUpperCase() {
         int x = 0;	
         uppercaseOK = false;
 
         while ( x < password.length()) {
 
            if (Character.isUpperCase(password.charAt(x))) {
 
               uppercaseOK = true;
               x++;         
            }
         }
      }  
   // checkDigit
      public void checkDigit () {
 
         int x = 0;
         digitOK = false;
 
         while ( x < password.length()) {
 
            if (Character.isDigit(password.charAt(x))) {
 
               digitOK = true;
 
               x++;         
            }
         }
      }
   // reportValidity
      public void reportValidity () throws IOException {
 
 
         if (digitOK && lowercaseOK && uppercaseOK && lengthOK) {
 
            System.out.print(" The password is valid."); }
 
         if (lengthOK != true) {
            System.out.print(" The password is invalid. Its length must be at least 6 characters."); }
         if ( lowercaseOK != true) {
            System.out.print(" The password is invalid. There must be at least 1 lower case letter."); } 
         if (uppercaseOK != true) {
            System.out.print(" The password is invalid. There must be at least 1 upper case letter."); }
         if (digitOK != true) {
            System.out.print(" The password is invalid. There must be at least 1 digit."); }
 
      }
 
   // print Report
 
      public void printReport () throws IOException {
 
         totalPasswords = passwordCount;
         outputFile = new PrintWriter("Passwordlist.txt");
 
         if (digitOK && lowercaseOK && uppercaseOK && lengthOK) {
 
            outputFile.print("The password is valid."); }
 
         if (lengthOK != true) {
            outputFile.print(" The password is invalid. Its length must be at least 6 characters."); }	
         if ( lowercaseOK != true) {
            outputFile.print(" The password is invalid. There must be at least 1 lower case letter."); } 
         if (uppercaseOK != true) {
            outputFile.print(" The password is invalid. There must be at least 1 upper case letter."); }
         if (digitOK != true) {
            outputFile.print(" The password is invalid. There must be at least 1 digit."); }
 
         outputFile.close();
      } // end printreport  
 
   } // End PWChecker

The output data looks like this:
Please follow along with the program to verify your passwords.
Please enter your name: Scot
Please enther the number of passwords you need to check: 05
Please enter each password: goaT321
Please enter each password: goaT321abc123
Please enter each password: abc123plant1231
Please enter each password: plant1231abc21321
Please enter each password: abc21321122132kdsd

the loop is also going on continuously

nvm im sorry...I see it now

just figuring out how to get the loop to stop, it doesn't move on to the method Im using to print the passwords and whether they were valid or not. I just have to keep reading and figure out the code, thank you so much.