use strict;
use warnings;

my @arr = (1, 2);
print qq{At initialisation\n     Contents are @arr\n};

assignTo(@arr);
print qq{     Contents now @arr\n};

listArgs(@arr);
print qq{     Contents now @arr\n};

loopOver(@arr);
print qq{     Contents now @arr\n};

refTo(@arr);
print qq{     Contents now @arr\n};

shiftArgs(@arr);
print qq{     Contents now @arr\n};

useDirect(@arr);
print qq{     Contents now @arr\n};

sub assignTo
{
    my @temp = @_;
    print qq{In assignTo - assign to \@_\n};
    map { $_ ++ } @temp;
    @_ = @temp;
}

sub listArgs
{
    my ($var1, $var2) = @_;
    print qq{In listArgs - list of lexicals\n};
    $var1 ++;
    $var2 ++;
}

sub loopOver
{
    print qq{In loopOver - loop over \@_\n};
    $_ ++ for @_;
}

sub refTo
{
    my ($rsVar1, $rsVar2) = \(@_);
    print qq{In refTo - take reference to \@_ elements\n};
    $$rsVar1 ++;
    $$rsVar2 ++;
}

sub shiftArgs
{
    my $var1 = shift;
    my $var2 = shift;
    print qq{In shiftArgs - lexicals via shift\n};
    $var1 ++;
    $var2 ++;
}

sub useDirect
{
    print qq{In useDirect - increment elements directly\n};
    $_[0] ++;
    $_[1] ++;
}
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