I use XML::Smart several times, I like this xml module, It is very easy to use! but i meet a strange problem. when i get a numeric value from xml file which save some old status value, and use the current status numeric value subtract the old value, the value is negative with the true result. for example: 
xml file:
<global_status>
......
 <status name="Uptime" value="816078" value_var="30"/>
</global_status>

code:
    my $now_value = scalar($_->[1]);
    my $last_value = $last_status_data->{value};
    $value_var = $now_value - $last_value;

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I print three value: name: Uptime, last_value: 816078, now_value: 816125, value_var: -47 the true result should be 47, but i get -47. I can solve the problem with: 
    my $last_value = $last_status_data->{value}+0;

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but i want to know why the negative result is generated? Thanks a lot! Robin

In reply to why the subtract result is negative when i use XML::Smart! by Robincui

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