Question

I need a function that returns whether the given string contains at least x special characters.

I prefer it shouldn’t be hardcoded.

Pseudo code:

public bool IsValid(string password, int minSpecialCharacters)
{
  if (!string.IsNullOrWhiteSpace(password))
    return
      password.Count(c => char.IsSpecialCharacter(c)) < minSpecialCharacters;
  return true;
}

Answer 1

Use char.IsLetterOrDigit, negated:

public bool IsValid(string password, int minSpecialCharacters)
{
    return password.Count(c => !char.IsLetterOrDigit(c)) >= minSpecialCharacters;
}