On Thu, Dec 12, 2013 at 3:01 AM, bob gailer <bgai...@gmail.com> wrote: > One student (PhD in Physics) looked at X = X + 1 and said "no it doesn't".
Yeah, which is why some languages (I first met it with Pascal) spell that as "X *becomes* X + 1"... but regardless of what you call it, there's a fundamental difference between algebra (where every line is a statement of truth) and imperative programming (which may change state as time progresses). What's called a "variable" in programming really can vary; in maths, it's really just an "unknown". This is a difference that, one way or another, just has to be taught. > Another wrote his first program. I took one look at it and saw the mistakes. > I explained how to walk thru the program step by step. He exclaimed "In that > much detail?". You mean a dry run [1]? Yes, can be tedious. Can also be very VERY valuable, especially if done verbally to another programmer, as a means of spotting differences between what the programmer thinks something does and what the language thinks it does. x = a * b + c "Set x to a times the sum of b and c." ChrisA [1] http://foldoc.org/dry+run -- https://mail.python.org/mailman/listinfo/python-list
