This will decrease the number of possible password combinations,

Yes.

and actually make password weaker

No.

In general, the second does not necessarily follow from the first. Blacklisting password "password" decreases the number of possible combinations, for example.

In this particular case, it also makes the password stronger since the hashes of all alphabetic passwords of length 14 or less are known. (I don't remember for which hashing algorithm.)

What password is stronger? The one which includes 8 characters from the [A-Z0-9] set, or one which includes 6 characters from the [A-Z] and 2 from [0-9]?

The one that includes 1 from [A-Z], 1 from [0-9] and 6 from [A-Z0-9].

In reply to Re^3: Please Review First Program: Random Password Generator by ikegami
in thread Please Review First Program: Random Password Generator by hakkum

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.