#!/usr/bin/perl -w

# EXAMPLE06 -- this script demonstrates passing arguments to subroutines.
#              (bmy, 6/8/09)

#------------------------------------------------------------------------------
# REFERENCE SECTION  
#------------------------------------------------------------------------------

require 5.003;    # Need this version of Perl or newer
use strict;       # "IMPLICIT NONE" -- force all declarations to be explicit

#------------------------------------------------------------------------------
# SUBROUTINE SECTION
#------------------------------------------------------------------------------

sub oneArgument($) {
  
  # Perl passes arguments to subroutines in one long array which is named
  # @_.  Here we have to split the arguments off from the @_ input array.
  my ( $arg1 ) = @_;

  # Print arguments
  print "\#\#\# In routine oneArgument! \#\#\#\n";
  print "The 1st argument is $arg1.\n";

  # Return normally
  return(0);
}

#------------------------------------------------------------------------------

sub twoArguments($$) {

  # Extract individual arguments from @_ input array
  my ( $arg1, $arg2 ) = @_;

  # Print arguments
  print "\#\#\# In routine twoArguments! \#\#\#\n";
  print "The 1st argument is $arg1.\n";
  print "The 2nd argument is $arg2.\n";

  # Return normally
  return(0);
}

#------------------------------------------------------------------------------

sub threeArguments($$$) {

  # Extract individual constituents from @_ input array
  my ( $arg1, $arg2, $arg3 ) = @_;

  # Print arguments
  print "\#\#\# In routine threeArguments! \#\#\#\n";
  print "The 1st argument is $arg1.\n";
  print "The 2nd argument is $arg2.\n";
  print "The 3rd argument is $arg3.\n";

  # Return normally
  return(0);
}

#------------------------------------------------------------------------------

sub main() {

  # Example of passing arguments to subroutines

  # Error check # of arguments
  if    ( scalar( @ARGV ) == 1 ) { &oneArgument( @ARGV );    }
  elsif ( scalar( @ARGV ) == 2 ) { &twoArguments( @ARGV );   }
  elsif ( scalar( @ARGV ) == 3 ) { &threeArguments( @ARGV ); } 
  else { 
    print "Usage: example06 ARG1 [ ARG2 [ ARG3 ]]\n";
    exit(1);
  } 

  # Return normally
  return(0);
}

#------------------------------------------------------------------------------
# EXECUTABLE SECTION
#------------------------------------------------------------------------------

# Call the main subroutine
# User-written subroutines are denoted by "&"
&main();

# NOTE: $? is the error code variable.  It denote
exit($?);