When I substituted 'eq' versus '==' it works.
Not sure why though...
Ken
At 03:07 PM 7/24/2005, John Deighan wrote:
At 02:20 PM 7/24/2005, Ed Chester wrote:
John Deighan::
> Is there a safe way to compare 2 floating point numbers in Perl? [snip]
> My debugger says that they're both '630.24' [snip]
> However, the == test fails and the != test succeeds
can you post code with the comparison == that fails ?
if the debugger says they're the same, they're very very probably the same.
are you sure the variable (or whatever) you're giving to == are
really what you
want them to be?
there are lots of ways to compare numbers, right down to looping over the
bits
and logically
XNORing them.
Sorry about the lack of sample code, but I know that people who work with
floating point numbers know about this problem, and I was wondering what
the best solution was. Here is sample code with output. Note that I'm not
formatting the output or rounding or anything - just printing out the
contents of the 2 variables.
my $sum1 = -237.15;
my $sum2;
$sum2 += -26.35;
$sum2 += -26.35;
$sum2 += -26.35;
$sum2 += -26.35;
$sum2 += -26.35;
$sum2 += -26.35;
$sum2 += -26.35;
$sum2 += -26.35;
$sum2 += -26.35;
print("sum1 = $sum1\n");
print("sum2 = $sum2\n");
if ($sum1 == $sum2) {
print("EQUAL\n");
}
else {
print("NOT EQUAL\n");
}
OUTPUT:
sum1 = -237.15
sum2 = -237.15
NOT EQUAL
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