You have been asked to write a username validation program for a small website. The website has specific rules on what constitutes a valid username, including: All usernames must be between 8 and 15 characters long Usernames can only contain alphabetic (a-z and A-Z) and numeric characters (0-9) - no special characters are allowed. The first character in a username cannot be a digit Usernames must contain at least one uppercase character Usernames must contain at least one lowercase character Usernames must contain at least one numeric character Write a program that asks the user to enter in a username and then examines that username to make sure it complies with the rules above. Here's a sample running of the program - note that you want to keep prompting the user until they supply you with a valid username:

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Explanation:

Python program to validate username and passwords and if invalid then fix the password to generate valid passwords

'''

import string

import random

# function to validate username

def username_validation(username):

              lowercase_letters = string.ascii_lowercase # string of all lowercase letters

              uppercase_letters = string.ascii_uppercase # string of all uppercase letters

              digits = string.digits

              num_uppercase = 0

              num_lowercase = 0

              num_digits = 0

              num_invalid = 0

              for letter in username:

                             if letter in lowercase_letters:

                                            num_lowercase = num_lowercase + 1

                             elif letter in uppercase_letters :

                                            num_uppercase = num_uppercase + 1

                             elif letter in         digits:

                                            num_digits = num_digits + 1

                             else:

                                            num_invalid = num_invalid + 1

              valid_start_end = not(username[0] in digits) and not(username[-1] in digits)

              print('* Length of username: %d'%(len(username)))

              print('* All characters are alpha-numeric: '),

              print(num_invalid == 0)

              print('* First & last characters are not digits: '+str(valid_start_end))

              print('* # of uppercase characters in the username: %d' %(num_uppercase))

              print('* # of lowercase characters in the username: %d' %(num_lowercase))

              print('* # of digits in the username: %d' %(num_digits))

              return(valid_start_end,num_uppercase,num_lowercase,num_digits,num_invalid)

# function to validate password  

def password_validation(username,password):

              while True:

                             (username_contained,num_lowercase,num_uppercase,num_special_chars,num_digits,num_invalid) = password_validation(username,password)

                             if(len(password) >= 8 and (not username_contained) and num_lowercase > 0 and num_uppercase > 0 and num_special_chars > 0 and num_invalid == 0):

                                            return password

                             if num_lowercase == 0:

                                            pos = random.randint(0,len(password)-1)

                                            letter = random.randint(0,len(lowercase_letters)-1)

                                            temp_password = password[0:pos] + lowercase_letters[letter]+ password[pos:]

                                            password = temp_password

                                            print('')

                                            print('* Adding a random lowercase character at a random position: '+password)

                             if num_uppercase == 0:

                                            pos = random.randint(0,len(password)-1)

                                            letter = random.randint(0,len(uppercase_letters)-1)

                                            temp_password = password[0:pos] + uppercase_letters[letter]+ password[pos:]

                                            password = temp_password

                                            print('* Adding a random uppercase character at a random position: '+password)

                             if num_special_chars == 0:

                                            pos = random.randint(0,len(password)-1)

                                            letter = random.randint(0,len(special_chars)-1)

                                            temp_password = password[0:pos] + special_chars[letter]+ password[pos:]

                                            password = temp_password

                                            print('* Adding a random special character at a random position: '+password)

                             if num_digits == 0:

                                            pos = random.randint(0,len(password)-1)

                                            letter = random.randint(0,len(digits)-1)

                                            temp_password = password[0:pos] + digits[letter]+ password[pos:]

                                            password = temp_password

                                            print('* Adding a random digit character at a random position: '+password)

                             if num_invalid > 0:

                                            i=0

                                            while i <len(password):

                                                           if password[i] not in valid_letters:

                                                                          temp_password = password[0:i] + password[i+1:]

                                                                          password = temp_password

                                                           else:

                                                                          i = i +1

                                            print('* Removing the invalid character from

                             (username_contained,num_lowercase,num_uppercase,num_special_chars,num_digits,num_invalid) = password_validation(username,password)

                             if(len(password) >= 8 and (not username_contained) and num_lowercase > 0 and num_uppercase > 0 and num_special_chars > 0 and num_invalid == 0 and num_digits > 0):

                                            break

                             else:

                                            print('* Length of password: %d' %(len(password)))

                                            print('* Username is part of password : '+str(username_contained))

                                            print('* # of uppercase characters in the password: %d' %(num_uppercase))

                                            print('* # of lowercase characters in the password: %d' %(num_lowercase))

                                            print('* # of digits in the password: %d' %(num_digits))

                                            print('* # of special characters in the password: %d'%(num_special_chars))

                                            print('* # of invalid characters in the password: %d' %(num_invalid))

                                            print('Password is invalid, please try again')

                                            choice = raw_input('\nWould you like us to fix your password for you? ')

                                            if choice.lower() == 'yes':

                                                           password = password_fixer(username,password)

                                                           print('Your new password is '+password)

                                            else:      

                                                           password = raw_input('\nEnter a password: ')

              print('Password is valid!')              

#call the main function  

if __name__ == "__main__":

              main()  

#end of program

###The full code is more than 5000 characters which is above character limit, so kindly check the below image for the complete code screenshot.

hey! im not 100 percent sure but im pretty sure that what you want to do is not possible : (

explanation: