fig06_08.pl

PERL语言资料 可以用于PERL程序设计

#!usr/bin/perl
# Fig 6.8: fig06_08.pl
# Syntax for calling a subroutine.

# subroutine with no arguments defined before it is used
sub definedBeforeWithoutArguments
{
   print "definedBeforeWithoutArguments\n";
}

# subroutine with arguments defined before it is used
sub definedBeforeWithArguments
{
   print "definedBeforeWithArguments: @_\n";
}

# calling subroutines that are defined before use
print "------------------------------\n";
print "Subroutines defined before use\n";
print "------------------------------\n";
print "Using & and ():\n";
&definedBeforeWithoutArguments();            
&definedBeforeWithArguments( 1, 2, 3 );      

print "\nUsing only ():\n";
definedBeforeWithoutArguments();             
definedBeforeWithArguments( 1, 2, 3 );      

print "\nUsing only &:\n";
&definedBeforeWithoutArguments;              
print "\"&definedBeforeWithArguments 1, 2, 3\"",
      " generates a syntax error\n";       

print "\nUsing bareword:\n";
definedBeforeWithoutArguments;              
definedBeforeWithArguments 1, 2, 3;              

# calling subroutines that are not defined before use
print "\n-----------------------------\n";
print "Subroutines defined after use\n";
print "-----------------------------\n";
print "Using & and ():\n";
&definedAfterWithoutArguments();            
&definedAfterWithArguments( 1, 2, 3 );      

print "\nUsing only ():\n";
definedAfterWithoutArguments();             
definedAfterWithArguments( 1, 2, 3 );      

print "\nUsing only &:\n";
&definedAfterWithoutArguments;              
print "\"&definedAfterWithArguments 1, 2, 3\"",
      " generates a syntax error\n";       

print "\nUsing bareword:\n";
definedAfterWithoutArguments; 
print "\"definedAfterWithoutArguments\" causes no action\n";
print "\"definedAfterWithArguments 1, 2, 3\"",
      " generates a syntax error\n";       

# subroutine with no arguments defined after it is used
sub definedAfterWithoutArguments
{
   print "definedAfterWithoutArguments\n";
}

# subroutine with arguments defined after it is used
sub definedAfterWithArguments
{
   print "definedAfterWithArguments: @_\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.                     #
###########################################################################