#!/usr/bin/perl

use strict;
use warnings;

aaa("Hello world");

sub aaa
{
    my $arg = shift;
    my $quit = shift;

    print("I am aaa, arg = $arg\n");
    exit 0 if ($quit);
    bbb("hello bbb");
}

sub bbb
{
    my $arg = shift;
    print("I am bbb, arg = $arg\n");
    ccc("hello ccc");
}

sub ccc
{
    my $arg = shift;
    print("I am ccc, arg = $arg\n");
    aaa("hello aaa", 42);
}

__END__