Lab: Password

Validating passwords.

Goals

• Practice iterating through a string
• Practice using the ctype library
• Practice using Boolean variables

It’s important to use passwords that are not easy to guess. Many websites require passwords that meet particular criteria for alphabetic and non-alphabetic characters.

In this lab, you’ll prompt the user for a password, which will then be checked using a function called check() that you’ll complete. If the password contains at least one uppercase letter, one lowercase letter, one number, and one symbol, the function should return true. Otherwise, it returns false.

You may recognize this exercise from the Pseudocode assignment we completed earlier this year.

Here’s your starting code:

// Check that a password has at least one lowercase letter, uppercase letter, number and symbol

#include <cs50.h>
#include <stdio.h>

bool valid(string password);

int main(void)
{
    string password = get_string("Enter your password: ");
    if (valid(password))
    {
        printf("Your password is valid!\n");
    }
    else
    {
        printf("Your password needs at least one uppercase letter, lowercase letter, number, and symbol\n");
    }
}

// TODO: Complete the Boolean function below
bool valid(string password)
{
    return false;
}

Hints

• Since you need to find at least one of each type of character, you may want to create a boolean variable for each, setting it to false. Then, if you find a number, for example, you can set that boolean to true. If all booleans are true at the end of the function, you’ve met all the criteria.

How to Test Your Code

You can also execute the below to evaluate the correctness of your code using check50. But be sure to compile and test it yourself as well!

check50 scienceacademy/problems/2024ap/password

How to Submit

Execute the below:

submit50 scienceacademy/problems/2024ap/password