use strict;
#這里是兩個數組
my @i =('1','2','3');
my @j =('a','b','c');

#在進行處理之前，我們把他們先打印出來，看一看他們的樣子
print "In main program before calling subroutine:i="."@i/n";
print "In main program before calling subroutine:j="."@j/n";

#然后我們通過子程序進行處理
reference_sub(@i,@j);
print "In main program after calling subroutine:i="."@i/n";
print "In main program after calling subroutine:j="."@j/n";
#下面是子程序
sub reference_sub
{
 my (@i,@j)=@_;
 print "In subroutine:i="."@i/n";
 print "in subroutine:j="."@j/n";

 #這里我們對@_的處理用pop,和shift來進行
 push(@i,'4');
 shift(@j);
}

F:/>perl/a.pl
In main program before calling subroutine:i=1 2 3
In main program before calling subroutine:j=a b c
In subroutine:i=1 2 3 a b c
in subroutine:j=
In main program after calling subroutine:i=1 2 3
In main program after calling subroutine:j=a b c
F:/>

use strict;

#這里是兩個數組
my @i =('1','2','3');
my @j =('a','b','c');

#在進行處理之前，我們把他們先打印出來，看一看他們的樣子
print "In main program before calling subroutine:i="."@i/n";
print "In main program before calling subroutine:j="."@j/n";

#然后我們通過子程序進行處理
reference_sub(/@i,/@j);#在這里我們添加了反斜線，也就是pass byreference（傳入引用，在大駱駝書中第六章翻譯）
print "In main program after calling subroutine:i="."@i/n";
print "In main program after calling subroutine:j="."@j/n";
#下面是子程序
sub reference_sub
{
 my ($i,$j)=@_;#引用也是一種特殊的數據形式，它們在@_中都被當成標量變量來儲存
 print "In subroutine:i="."@$i/n";所以這里引用它們的時候，我們在他們前面添加了兩個符號，@代表這是一個數組，$代表著是一個二次引用。
 print "in subroutine:j="."@$j/n";
    print "In subroutine:the third element is $$j[2]/n";#當引用數組中的一個元素的時候第一個$和后面的j[2]代表數組中的第三個元素，而第二個$代表的就是二次引用
 #這里我們對@_的處理用pop,和shift來進行
 push(@$i,'4');
 shift(@$j);
}

F:/>perl/a.pl
In main program before calling subroutine:i=1 2 3
In main program before calling subroutine:j=a b c
In subroutine:i=1 2 3
in subroutine:j=a b c
In subroutine:the third element is c
In main program after calling subroutine:i=1 2 3 4
In main program after calling subroutine:j=b c
F:/>