20 Aug
2001
20 Aug
'01
4:17 a.m.
On Mon, 20 Aug 2001, Jeffrey S. Sharp wrote:
"To the man who has a hammer, the whole world looks like a nail." I have
seen SEVERAL products of that system who sincerely believed that ANYTHING
that COULD be done with recursion SHOULD be done with recursion, including
simple FOR loops. I consider recursion to be a clever/cute/curiousity,
not the fundamental basis for a programming model.
The canonical example for explaining recursion is factorial. In anything
resembling real world, a FOR loop works better.
I've used recursion for "walking the tree" of a subdirectory
structure. It was fun and easy, but the stack load was excessive.
I eventually switched to a linked list of subdirectories with a pointer of
which dirs were done chasing a pointer of new dirs being added.
In order for recursion to be stable, one would want more than a 64K
segment for stack.
Yes.
It's how C copies a string. The character at the location pointed to by
the S pointer is copied to the location pointed to by the T pointer, both
pointers are incremented, and it continues until the character that was
copied had a value of zero (C uses null-termination to mark the end of
strings).
--
Grumpy Ol' Fred cisin(a)xenosoft.com
On the other hand, they're not that bad. I like
Lisp-like languages.
(0) Prefix notation throughout the language is nicely consistent.
(1) Little or no need for precedence rules is somewhat nice.
(2) Proper indentation and editor can alleviate paren hell.
I guess those reasons don't really seem tera-compelling. To each, his
own.
They're pretty good.
I would like my students to understand the concepts of precedence rules,
but I would rather see a program use parentheses than to rely on the
precedence rules.
Encouraged?
Some of the teachers won't let their students do a
program to count to 10 WITHOUT recursion! They can't imagine doing
something like Fibonacci sequence WITHOUT using recursion.
Those teachers are
probably of the mathy kind. Either their imagination
is limited to recursion, or they think they're being much less deceptive
by using recursion instead of the special cases of it rolled into a
particular language's looping constructs. Either way, it's just going to
be confusing to new students. How can you do
a non-trivial program with recursion without stack
overflow?
Very carefully, but it can happen.
while(*T++=*S++);
Was this an actual program fragment?