#!/usr/bin/perl
# Fig 6.13: fig06_13.pl
# Recursive factorial subroutine

# call function factorial for each of the numbers from 
# 0 through 10 and display the results
foreach ( 0 .. 10 ) {
   print "$_! = " . factorial( $_ ) . "\n";
}

# factorial recursively calculates the factorial of the 
# argument it receives
sub factorial
{
   my $number = shift;   # get the argument

   if ( $number <= 1 ) { # base case
      return 1;
   }
   else {                # recursive step
      return $number * factorial( $number - 1 );
   }
}



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