Perl |模块
Perl 中的模块是执行一组编程任务的相关子程序和变量的集合。Perl 模块是可重用的。各种各样的 Perl 模块可以在综合 Perl 存档网络(CPAN)上获得。这些模块涵盖了广泛的类别，如网络、CGI、XML 处理、数据库接口等。
Creating a Perl Module
模块名称必须与包的名称相同，并应以结尾。pm 分机。
示例:Calculator.pm
package Calculator;
# Defining sub-routine for Multiplication
sub multiplication
{
# Initializing Variables a & b
$a = $_[0];
$b = $_[1];
# Performing the operation
$a = $a * $b;
# Function to print the Sum
print "\n***Multiplication is $a";
}
# Defining sub-routine for Division
sub division
{
# Initializing Variables a & b
$a = $_[0];
$b = $_[1];
# Performing the operation
$a = $a / $b;
# Function to print the answer
print "\n***Division is $a";
}
1;
这里，文件的名称是“Calculator.pm”，存储在 Calculator 目录中。注意 1；写在代码的末尾，向解释器返回一个真值。Perl 接受任何真实的东西，而不是 1
To import this calculator module, we use require or use functions. To access a function or a variable from a module, :: is used. Here is an example demonstrating the same:
示例:Test.pl
#!/usr/bin/perl
# Using the Package 'Calculator'
use Calculator;
print "Enter two numbers to multiply";
# Defining values to the variables
$a = 5;
$b = 10;
# Subroutine call
Calculator::multiplication($a, $b);
print "\nEnter two numbers to divide";
# Defining values to the variables
$a = 45;
$b = 5;
# Subroutine call
Calculator::division($a, $b);
输出:
Using Variables from modules
不同包中的变量可以通过在使用前声明来使用。下面的例子演示了这个 T1】例子:Message.pm
#!/usr/bin/perl
package Message;
# Variable Creation
$username;
# Defining subroutine
sub Hello
{
print "Hello $username\n";
}
1;
Perl 文件访问模块如下 示例
#!/usr/bin/perl
# Using Message.pm package
use Message;
# Defining value to variable
$Message::username = "Geeks";
# Subroutine call
Message::Hello();
输出:
Perl provides various pre-defined modules which can be used in the Perl programs anytime. Such as: ‘strict’, ‘warnings’, etc.
示例:
#!/usr/bin/perl
use strict;
use warnings;
print" Hello This program uses Pre-defined Modules";
输出:
Hello This program uses Pre-defined Modules
