Question

Write a Java program (name it PasswordTest) that reads from the user a string input (representing a password) and determines whether the password is “Valid Password” or “Invalid Password”. A valid password has at least 7 characters and includes at least one lower-case letter, at least one upper-case letter, at least one digit, and at least one character that is neither a letter nor a digit. Your program will need to check each character in the string in order to render a verdict. For example, CS5000/01 is invalid password; however, Cs5000/01 is a valid password. The program should display the entered password and the judgment as shown in the following sample runs:

Entered Password: CS5000/01

Verdict: Invalid Password

Entered Password: Cs5000/011

Verdict: Valid Password

Entered Password: MyOldDogK9

Verdict: Invalid Password

Entered Password: MyOldDogK9#

Verdict: Valid Password

Entered Password: Ab1#

Verdict: Invalid Password

Document your code, and organize and space out your outputs as shown. Design your program such that it allows the user to re-run the program with different inputs in the same run (i.e., use a sentinel loop structure).

Answer 1

Thanks for the question.


Below is the code you will be needing  Let me know if you have any doubts or if you need anything to change.


Thank You !!


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import java.util.Scanner;

public class PasswordValidator {


    public static boolean validPassword(String password) {


        if (password == null) return false;
        int length = 0;
        boolean containLowerCase = false;
        boolean containsUpperCase = false;
        boolean containsDigit = false;
        boolean containsSpecialCharacter = false;

        for (int i = 0; i < password.length(); i++) {
            length += 1;
            char letter = password.charAt(i);
            if ('a' <= letter && length <= 'z') containLowerCase = true;
            else if ('A' <= letter && length <= 'Z') containsUpperCase = true;
            else if ('0' <= letter && letter <= '9') containsDigit = true;
            else containsSpecialCharacter = true;
        }

        return length >= 7 && containLowerCase && containsUpperCase &&
                containsDigit && containsSpecialCharacter;
    }

    public static void main(String[] args) {

        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter Password: ");
        String password = scanner.nextLine();
        if (PasswordValidator.validPassword(password)) {
            System.out.println("Verdict: Valid Password");
        } else {
            System.out.println("Verdict: Invalid Password");
        }
    }
}