I'm practising my coding - pretty new to this - and i'm trying to create a login system, all is working well so far but i'm trying to use a while loop to maximise the number of user attempts at inputting the correct password. Even if the user inputs the correct password, the loop will carry on until the loop is completed and will continue to say carry on.

login = {
    "alex": "dog123"
}
passkey = login.values()
correct_user = True


while correct_user:
    user = input("Please input your username ")
    if user in login:
        print(f'Hello {user}, please input your password.')
        correct_user = False
    else:
        print("Invalid user")

attempt = 0
max_attempts = 3
correct_password = True

while correct_password:
    password = input(">")
    if password in passkey:
        print(f"""Welcome back {user}! 
How can i help you today?""")
        correct_password = False
    else:   
        while attempt < max_attempts:
            print("try again")
            attempt  = 1
            password = input(">")
            if password in passkey:
                correct_password = False
        else:
            print("too many guesses!")
            break

CodePudding user response：

You can shorten that to:

attempt = 0
max_attempts = 3
passkey = ['sesame']

while attempt < max_attempts:
    password = input(">")
    if password in passkey:
        print(f"""Welcome back {user}! How can i help you today?""")
        break
    else:
        attempt  = 1
        if attempt <3:
            print("try again")    
else:
    print("too many guesses!")

CodePudding user response：

Try this.

login = {
    "alex": "dog123"
}
passkey = login.values()
correct_user = True


while correct_user:
    user = input("Please input your username ")
    if user in login:
        print(f'Hello {user}, please input your password.')
        correct_user = False
    else:
        print("Invalid user")

attempt = 0
max_attempts = 3
correct_password = True

while correct_password:
    if attempt < max_attempts: # checks if an attempt is left.
        password = input(">")
        if password == login[user]: # Check password equal current userpassword.
            print(f"""Welcome back {user}! 
    How can I help you today?""")
            correct_password = False
        else:
            print("Invalid password")
            attempt  = 1
    else: # print too many attempts 
        print("Too many attempts")
        correct_password = False

Don't use password in passkey to check that if password is correct or not. Why?

Explanation

Let say you have more than one users

login = {
    "alex": "dog123",
    "alice": "cat123"

}

If you use in and check that if password is in passwords list then you face a bug

When

1. Example

• If user is equal alex and password is cat123 then you code don't print that password is incorrect.

So use == and check if password == login[user] here user and password are then one that user enters.