fig20_06.pl

PERL语言资料 可以用于PERL程序设计

#!/usr/bin/perl
# Fig. 20.6: fig20_06.pl
# Using class LinkedList.

use warnings;
use strict;
use LinkedList;

my $ll = new LinkedList();
my $choice;

instructions();

do {              
   print( "? " );
   chomp( $choice = <STDIN> );
   
   insertIt() if ( $choice eq 'i' ); 
   
   deleteIt() if ( $choice eq 'd' );

   instructions() if ( $choice eq '?' );

   print( "\n" );
} while ( $choice ne 'q' );

# inserts a node in the list and outputs the list
sub insertIt
{
   print( "Enter a string: " );
   chomp( my $item = <STDIN> );
   $ll->insertNode( $item );
   $ll->printList();
}

# deletes a node from the list and outputs the list
sub deleteIt
{
   print( "Enter string to be deleted: " );
   chomp( my $item = <STDIN> );
   print( $ll->deleteNode( $item )? "$item deleted.\n" : 
        "$item not found.\n" ); 
   $ll->printList();
}

# displays the instructions
sub instructions 
{
   print << 'DONE';
Enter your choice:
   i to insert an element into the list.
   d to delete an element from the list.
   q to end.      
   ? to print instructions.
DONE
}

###########################################################################
#  (C) Copyright 2001 by Deitel & Associates, Inc. and Prentice Hall.     #
#  All Rights Reserved.                                                   #
#                                                                         #
#  DISCLAIMER: The authors and publisher of this book have used their     #
#  best efforts in preparing the book. These efforts include the          #
#  development, research, and testing of the theories and programs        #
#  to determine their effectiveness. The authors and publisher make       #
#  no warranty of any kind, expressed or implied, with regard to these    #
#  programs or to the documentation contained in these books. The authors #
#  and publisher shall not be liable in any event for incidental or       #
#  consequential damages in connection with, or arising out of, the       #
#  furnishing, performance, or use of these programs.                     #
###########################################################################