On 14 Nov 2002 12:40:38 +0000, Anthony Williams
<[EMAIL PROTECTED]> wrote:
>I have uploaded lexical_compare.hpp to the yahoo files area. It contains
>implementations of the function template lexicalCompare.
Just a little comment and a couple of questions. The former is
actually just a matter of personal preference, so don't feel qualms
about ignoring it (well, not that the same advice isn't valid for the
questions too :-)
I would write the body as:
for (...) {
if(*first1 < *first2)
return -1;
else if(*first2 < *first1)
return +1;
}
if(first2 != last2)
return -1;
else if(first1 != last1)
return +1;
else
return 0;
The difference is in the order of the out-of-loop tests. Since we test
what is *not* exhausted (or empty since the beginning) I prefer to
check the second sequence first, so that the order of the tests that
give -1 is the same inside and out of the loop. In other words I
prefer to see first whether the first sequence is lexicographically
less. BTW once you rewrite it as above you realize that you can
further simplify it as:
for (...) {
if(*first1 < *first2)
return -1;
else if(*first2 < *first1)
return +1;
}
if(first2 != last2) // (*)
return -1;
return first1 != last1;
The questions are: a) as you know the SGI STL has such a template for
long time (lexicographical_compare_3way). Did you deliberately choose
a different name? Why? b) Did you really have problems without the
casts?
Genny.
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