While I strongly recommend a robust and tested pretty printer solution here is an example of how you could do it in a few lines of Perl. Not really very robust but you could do:

Update. Opps, wrong lang. Changed from trailing \ to \t indent continuation

my $wrap = 76;
my $tab  = 4;   # spaces occupied by tab
while(<DATA>) {
    do{ print; next } if length($_) < $wrap;
    do{ print "\n"; next } if m/^\s*$/;
    s/^(\s*)(?=\S)// or die "Choked on $_\n";
    my $indent = $1;
    my $l_wrap = $wrap - length($indent) - $tab;
    my @bits = $_ =~ m/\G(.{1,$l_wrap})\s+/gc;
    for ( my $i = 0; $i <@bits; $i++ ) {
        print $i == 0 ? "$indent$bits[$i]\n" : "$indent\t$bits[$i]\n";
    }
}


__DATA__
class ClassMyClassNameNoMatterHowLongItIsName:public BaseClass
{
    blah blah blah blah blah blah blah blah blah blah blah blah blah b
+lah blah blah blah blah blah blah blah blah blah blah blah blah blah 
+blah blah blah blah blah blah blah blah blah blah blah blah blah blah
+ blah
public:
    blah blah blah blah blah blah blah blah blah blah blah blah blah b
+lah blah blah blah blah blah blah blah
}

__END__
class ClassMyClassNameNoMatterHowLongItIsName:public BaseClass
{
    blah blah blah blah blah blah blah blah blah blah blah blah blah
        blah blah blah blah blah blah blah blah blah blah blah blah bl
+ah
        blah blah blah blah blah blah blah blah blah blah blah blah bl
+ah
        blah blah blah
public:
    blah blah blah blah blah blah blah blah blah blah blah blah blah
        blah blah blah blah blah blah blah blah
}
[download]

---

---

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! —

• How do I compose an effective node title?
• How do I post a question effectively?
• Markup in the Monastery

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:
	&		&
	<		&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.