Re: My floating point comparison does not work. Why ?

[hanspr]

If you create a text file x.txt with following data

227.20
1176.00
262.00
481.60
492.00
489.60
808.50
934.50
150.00
806.00
563.70
295.60
552.90
327.25
0.00
0.00
0.00

Then file x2.txt

7566.85

And then run this code

open (X,"< x.txt");
while ($n = <X>) {
    $n =~ s/\n|\r//g;   # same with or without
    $t += $n;
}
close X;
$st = `cat x2.txt`;
$st =~ s/\n|\r//g;  # same with or without
print "t  = $t\n";
print "st = $st\n";

if (equal($t,$st,5)) {
    print "Equal\n";
} else {
    print "Different\n";
}

sub equal {
    my ($A,$B,$dp) = @_;

    return sprintf("%.${dp}g",$A) eq sprintf("%.${dp}g",$B);
}

The result is

t  = 7566.85
st = 7566.85
Different

So the only reliable solution I have found till now is

sub equal {
    my ($A,$B,$dp) = @_;

    if ($A == $B) {
        return 1;
    } elsif ($A eq $B) {
        return 1;
    }
    return sprintf("%.${dp}g",$A) eq sprintf("%.${dp}g",$B);
}

Result

t  = 7566.85
st = 7566.85
Equal