Re: Should I learn C or Pascal?

[dewar@cs.nyu.edu (Robert Dewar)]

"An algorithm is just a set of instructions on how to accomplish a task. An
algorithm does not depend at all on any sort of programming "language". In
fact, I was taught that you should write out your "game plan" and psuedo
code before you even touch any sort of syntax in any language. Yes, I do
tend to write up my psuedo-code in a C-like syntax frequently but you
don't need to.

     Loop until variable is equal to 7
        Add 1 to variable
        Print out the following string to screen: ;-)
        end of loop

There's an algorithm written in plain english. It's a stupid algorithm,"

First of all "pseudo-code" is still written in a language, which has syntax
and semantics. The trouble with an algorithm written in "plain english"
like the above is that it is imprecise. For example does the string that
is written to screen include a leading blank? I have no idea from the above.

If variable is 2**32-1, does the above still work? I have no idea.

Are the strings on separate lines of the screen? I have no idea.

writing

   while variable /= 7 loop
      variable := variable + 1;
      put_line (";-)");
   end loop;

is less writing than you did, just as clear, and importantly, exactly
precise (I had to make some guesses as to what your intention was, but
if my guesses were wrong, the above is easily modified to accomodate
them).

Writing at a high semantic level is desirable, and your example would
have been much more effective if for example it had included universal
quantification over finite sets, but that too would better be written
in a well-defined language.

If you went a step further, and wrote non-effective computation steps
involving for example membership in infinite sets, then of course what
you wrote would not correspond to an executable program, but would still
be better written in a precise language (e.g. one of the many
specification languages like Z)

Writing in "plain english" may appeal to those who are petrified of
formal notation of any kind, but such people are not likely to get
very far in this field anyway!