package Text::numbers ;

# Developed by Rajiv Pant (Betul)  betul@rajiv.org   http://rajiv.org/


use strict ;
use integer ;



$Text::numbers::revision = '$Id: numbers_as_words.pm,v 1.0 1997/09/13 16:51:10 betul Exp betul $';

$Text::numbers::VERSION = '1.0' ;

'version' => <<'END_OF_FUNC',
sub version { return $VERSION ; }
END_OF_FUNC

$Text::numbers::AUTHOR = 'Rajiv Pant (Betul)  betul@rajiv.org   http://rajiv.org/' ;



sub as_words
{


my $NEGATIVE = 'negative' ;

# TO DO: In some locales, the term used is "minus".
#	As in "minus two point three degrees centigrade".


my $ZERO = 'zero' ;

my @ONES_AND_TEENS = ( '', qw (

one two three four five six seven eight nine
ten eleven twelve thirteen fourteen fifteen
sixteen seventeen eighteen nineteen

) ) ;


my @TENS = qw (

twenty thirty forty fifty sixty seventy eighty ninety

) ;


my $HUNDRED = 'hundred' ;

my @POWERS_OF_TEN = qw (

thousand million billion trillion quadrillion quintillion

) ;



my $number = shift ;


if ($number == 0)
{
	return $ZERO ;
}


my $result = '' ;


if ($number < 0)
{
	$result .= $NEGATIVE . ' ' ;
	$number = - $number ;
}


my $place = log10 ($number) / 3 ;


while ($place >= 0)
{

	my $h = ten_raised_to_power ($place * 3) ;

	my $hundreds = $number / $h ;
	
	if ($hundreds != 0)
	{
		$number -= $h * $hundreds ;

		$h = $hundreds / 100 ;
		
		if ($h != 0)
		{
			$hundreds -= $h * 100 ;
			$result .= $ONES_AND_TEENS[$h] . ' ' . $HUNDRED ;

		} # end if
		
		if ($hundreds != 0)
		{
			if ($h != 0) { $result .= ' ' } ;
			
			if ($hundreds < 20)
			{
				$result .= $ONES_AND_TEENS[$hundreds] ;

			} # end if ; begin else

			else
			{
				$h = $hundreds / 10 ;
				
				if ($h != 0)
				{
					$hundreds -= $h * 10 ;
					$result .= $TENS[$h - 2] ;
					

				} # end if
				
				if ($hundreds != 0)
				{
					$result .= '-' . $ONES_AND_TEENS[$hundreds] ;
				
				} # end if
				
			} # end else
			
		} # end if
		


		if ($place != 0)
		{
			$result .= ' ' . $POWERS_OF_TEN[$place - 1] ;
			
			if ($number != 0) { $result .= ', ' ; }
		
		} # end if
		
	} # end if

	--$place ;

} # end while

return $result ;

} # end sub as_words






# Some Mathematical Functions


sub ten_raised_to_power
{
	my $power = shift ;
	my $result ;

	for ($result = 1 ; --$power >= 0 ; $result *= 10) { ; }

	return $result ;

} # end sub ten_raised_to_power



# Returns the log to base 10 of the given number ;

sub log10
{
	my $given_number = shift ;
	my $power ;
	
	for ($power = 9 ; ( $given_number / ten_raised_to_power($power) ) == 0 ;
		--$power ) { ; }

	return $power ;	
	
} # end sub log10



1 ; # To make the package return a true value.