Comparing 2 similar strings?

[William Park]

How do you compare 2 strings, and determine how much they are "close" to
each other?  Eg.
    aqwerty
    qwertyb
are similar to each other, except for first/last char.  But, how do I
quantify that?

I guess you can say for the above 2 strings that
    - at max, 6 chars out of 7 are same sequence --> 85% max

But, for
    qawerty
    qwerbty
max correlation is
    - 3 chars out of 7 are the same sequence --> 42% max

(Crossposted to 3 of my favourite newsgroup.)

-- 
William Park <opengeometry at yahoo.ca>, Toronto, Canada
ThinFlash: Linux thin-client on USB key (flash) drive
           http://home.eol.ca/~parkw/thinflash.html