01: #! /usr/bin/perl
02: use warnings;
03: use strict;
04: 
05: # ============================================================
06: { # Beginn der Closure
07:     my $counter = 0;
08:     # ------------------------------------------------------------
09:     sub ZaehleHoch {
10:         $counter++;
11:     } # ZaehleHoch
12:     # ------------------------------------------------------------
13:     sub ZaehleRunter {
14:         $counter--;
15:     } # ZaehleRunter
16:     # ------------------------------------------------------------
17:     sub GibMirDenCounterWert {
18:         return $counter;
19:     } # GibMirDenCounterWert
20:     # ------------------------------------------------------------
21: 
22: } # Ende der Closure
23: # ============================================================
24: 
25: print &GibMirDenCounterWert(), "\n";
26: for my $i (1..20) {
27:     &ZaehleHoch();
28: } # for
29: print &GibMirDenCounterWert(), "\n";
30: for my $i (4..9) {
31:     &ZaehleRunter();
32: } # for
33: print &GibMirDenCounterWert(), "\n";