Hi Monks,

I was trying the code from Okay! What!?!?!? 
my $value1 = 14.4;
print "value1 = $value1\n";

my $value2 = 10 + 14.4 - 10;
print "value2 = $value2\n";

if ( $value1 == $value2 ) {
    print "value 1 equals value 2\n";
} else {
    print "value 1 does not equal value2\n";
}

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Output: 
value1 = 14.4
value2 = 14.4
value 1 does not equal value2

[download]

and from My floating point comparison does not work. Why ? 
$number = 1.80;
$premium = $number * ( 1 + 10/100 );
$expected = 1.98;
print "Number 1 : $premium \n";
print "Number 2 : $expected \n";
print "Not" if $expected != $premium;
print "Equal !! ";

[download]
Output: 
Number 1 : 1.98
Number 2 : 1.98
NotEqual !!

[download]

when I came up with the following behavior (tested on Perl 5.10.1 and on 5.18.2):

Swapping operands on the first sample code: 
my $value2 = 10 + 14.4 - 10;          # wrong evaluated

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my $value2 =  14.4 + 10 - 10;         # wrong evaluated

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my $value2 = 10 - 10 + 14.4;          # right evaluated

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Using eval: 
my $value2 = eval (10 + 14.4 - 10);   # right evaluated

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Using eval on the second sample code: 
$number = 1.80;
$premium = eval ($number * ( 1 + 10/100 ));
$expected = 1.98;
print "Number 1 : $premium \n";
print "Number 2 : $expected \n";
print "Not" if $expected != $premium;
print "Equal !! ";

[download]
Output: 
Number 1 : 1.98
Number 2 : 1.98
Equal !!

[download]


So, I got odd results depending on the order of the operands and right results on evaluating.

How can that be?

In reply to Results depending on evaluation order by fishy

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