perl - 我想访问子程序外部的私有(private)变量

Question

我试图在子例程之外访问子例程的私有(private)变量。如何做到这一点？

我尝试了我发布的问题代码，但它正在打印全局变量“名称”的值，并且条件是全局变量和私有(private)变量的名称必须相同。

 print("Please Enter Your First Name:\n");
 # declaration of global variable 
 $name = <>;
 YourFirstName_StudentID($name);
 sub YourFirstName_StudentID {
     print("My name is $name\n");
     print("Enter Your Student ID\n");
     my $name = <>;
 }
 #printing outside subroutine 
 print("Student Id is: $name");

当前输出为:请输入您的名字:我的名字是xyz

输入您的学生证学生ID是:xyz

但我想要这样请输入您的名字:我的名字是xyz

输入您的学生证学号是:1234567

Answer 1

这是一个例子，这里我们不需要使用全局变量。最好使用lexical variables :

use strict;
use warnings;

{   # <--- Make a scope so lexical variables do not leak out into
    #       subs declared later in the file..
    print("Please Enter Your First Name:\n");
    chomp (my $name = <>);
    my $id = YourFirstName_StudentID($name);
    print("Student Id is: $id\n");
}

sub YourFirstName_StudentID {
    #print("My name is $name\n");
    print("Enter Your Student ID\n");
    chomp( my $id = <>);
    return $id;  # <--- return local variable to caller
}