Here's a brief summary of the functions used in the program:

get_password_length() prompts the user to enter a password length and validates the input.
generate_salt() generates a random salt of a specified length.
derive_key() uses the PBKDF2 function from OpenSSL to derive a key from a master password and a salt.
generate_password() generates a password of a specified length using a pseudo-random sequence of characters from a defined alphabet and a key derived from a master password and a salt.
count_lowercase(), count_uppercase(), count_digits(), and count_symbols() count the number of lowercase letters, uppercase letters, digits, and symbols in a given string.
print_strength_meter() prints a description of the password strength based on the number of lowercase letters, uppercase letters, digits, and symbols in a given password.
The program requires the OpenSSL and BSD libraries to compile and run.