Perl 中的子程序

sub subroutine_name
{
   statement(s);
   return;
}

&subroutine_name; #calling without parameter
&subroutine_name(10);

#!/usr/bin/perl
my msg;

# defining three subroutines
sub ask_user {
   printf "Please enter something: ";
}
sub get_input {msg = <STDIN>;
   return msg;
}
sub show_message {
   printf "You entered:msg";
}
#calling subroutines
&ask_user;
&get_input;
&show_message;

Please enter something: Welcome to beginnersbook
You entered: Welcome to beginnersbook

#!/usr/bin/perl

# defining subroutine
sub printparams {
   printf "@_\n";
   return;
}
#calling subroutine
&printparams("This", "is", "my", "blog");

This is my blog

#!/usr/bin/perl

# defining subroutine
sub printparams {
   printf "First Parameter: _[0]\n";
   printf "Fourth Parameter:_[3]\n";
   return;
}
#calling subroutine
&printparams("This", "is", "my", "blog");

First Parameter: This
Fourth Parameter: blog

#!/usr/bin/perl

# defining subroutine
sub printparams {
   printf "First Parameter: _[0]\n";
   printf "Third Parameter:_[2]\n";
   printf "Fourth Parameter: _[3]\n";
   printf "Sixth Parameter:_[5]\n";
   return;
}

@array1 = ("This", "is", "text");
num = 100;
@array2 = ("Welcome", "here");
#calling subroutine
&printparams(@array1, @array2,num);

First Parameter: This
Third Parameter: text
Fourth Parameter: Welcome
Sixth Parameter: 100

#!/usr/bin/perl

sub DisplayMyHash{
   #copying passed hash to the hash
   my %hash = @_;

  for my key (keys %hash) {
    print "Key is:key and value is: hash{key}\n";
  }
}
%hash = ('Item1', 'Orange', 'Item2', 'Apple', 'Item3', 'Banana');

# Function call with hash parameter
DisplayMyHash(%hash);

Key is: Item1 and value is: Orange
Key is: Item2 and value is: Apple
Key is: Item3 and value is: Banana