perl 基础学习_子过程

renheshi

　　平时用C或C++编程的人，一看perl，应该感觉特别灵活吧，怎么这么多格式呀。
　　在过程调用的时候，会涉及到C中所谓的形参。这个在perl中，是这样的
　　sub testPro {
  my (@list1, @list2) = @_;
  }
　　这是定义一个字过程，其中有@_, @_之意是，传递的当前参数的集合。当在子过程中调用传递的参数是，形式是： $_[0], $_[1]
　　

$_[0]表示函数的第一个参数 
$_[1]表示函数的第二个参数 。

　　

参考

　　

@_ is the list of incoming parameters to a sub. So if you write a sub, you refer to the first parameter in it as $_[0], the second parameter as $_[1] and so on. And you can refer to $#_ as the index number of the last parameter:
sub demo {
print "Called with ",$#_+1," params\n";
print "First param was $_[0]\n";

Note that the English module adds in the ability to refer to the special variables by other longer, but easier to remember, names such as @ARG for @_ and $PID for $$. But use English; can have a detrimental performance effect if you're matching regular expressions against long incoming strings.