On 19 September 2015 at 17:02, Rod Smallwood <rodsmallwoo...@btinternet.com> wrote: > Its a while back but I seem to remember in BASIC you replaced a set of line > numbers with another of the same range but different code.
Blimey, I've never seen that. I do remember that ZX BASIC had a cool-but-dangerous feature: you could get it to evaluate an arbitrary string as if it were an expression. This meant you could do cool things in BASIC programs -- enter formulae such as "2*4+3.5" when the program wanted a numeric value, for instance. Then a friend showed me that you could also access the program's own variables. If the program had variables called a, b & c, you could also enter "a*b+c" and it would use the values. Which meant that if it /didn't/ have such variables, the program would crash out with an "unknown variable name" error... a sort of early "exploit". -- Liam Proven • Profile: http://lproven.livejournal.com/profile Email: lpro...@cix.co.uk • GMail/G+/Twitter/Flickr/Facebook: lproven MSN: lpro...@hotmail.com • Skype/AIM/Yahoo/LinkedIn: liamproven Cell/Mobiles: +44 7939-087884 (UK) • +420 702 829 053 (ČR)
