fig06_16.pl

PERL语言资料 可以用于PERL程序设计

#!/usr/bin/perl
# Fig. 6.16: fig06_16.pl
# Demontrating variable scope.

# before global variables are defined, call subroutine1
print "Without globals:\n";
subroutine1();

# define global variables
our $x = 7;
our $y = 17;

# call subroutine1 to see results with defined global variables
print "\nWith globals:";
print "\nglobal \$x: $x";
print "\nglobal \$y: $y\n";
subroutine1();
print "\nglobal \$x: $x";
print "\nglobal \$y: $y\n";
subroutine2();
# subroutine1 displays its own $x (lexical scope ) 
# and $y (dynamic scope) variables, then calls subroutine2
sub subroutine1
{
   my $x = 10;
   local $y = 5;
   print "\$x in subroutine1: $x\t(lexical to subroutine1)\n";
   print "\$y in subroutine1: $y\t(dynamic to subroutine1)\n";
   subroutine2();
}

# subroutine2 displays global $x and subroutine1's $y which
# has dynamic scope
sub subroutine2
{
   print "\$x in subroutine2: $x\t(global)\n";
   print "\$y in subroutine2: $y\t(dynamic to subroutine1)\n";
}



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