#!/usr/bin/perl
use strict;
use warnings;
use 5.010;

say "ohne: ".(-6.725/0.025);
say "int(): ".int(-6.725/0.025);
say "integer(): ".integer(-6.725/0.025);

sub integer {
    my $wert = shift (@_) || 0;
    return 'FEHLER' if $wert =~ /e\+?\d+$/;
    return 0 if $wert =~ /e-\d+$/;
    $wert = $1 if $wert =~ /^(.*?)\./;
    $wert = 0 if !$wert or $wert == -0;
    return $wert;
}