fig04_10.pl

PERL语言资料 可以用于PERL程序设计

#!/usr/bin/perl
# Fig. 4.10: fig04_10.pl
# Demonstrating the push, pop, shift and unshift functions.

# Use push to insert elements at the end of @array.
for ( $i = 1; $i <= 5; ++$i ) {
   push( @array, $i );            # add $i to end of @array
   print "@array\n";              # display current @array
}

# While there are more elements in @array, pop each element.
# Note the use of @array as a condition. When @array is empty, 
# the condition becomes false; otherwise, it is true.
while ( @array ) {
   $firstTotal += pop( @array );  # remove last element
   print "@array\n";              # display current @array
}

print "\$firstTotal = $firstTotal\n\n";

# Use unshift to insert elements at the front of @array.
for ( $i = 1; $i <= 5; ++$i ) {
   unshift( @array, $i );         # add $i to front of @array
   print "@array\n";              # display current @array
}

# While there are more elements in @array, remove each element
# with shift. 
while ( @array ) {
   $secondTotal += shift( @array );  # remove first element
   print "@array\n";                 # display current @array
}

print "\$secondTotal = $secondTotal\n";

###########################################################################
#  (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.                     #
###########################################################################