为什么我的程序即使在提示处什么也不输入的情况下工作？

Question

我有以下脚本提示输入用户名和密码并检查它们是否匹配。但是，即使我只是在提示时输入输入，但不输入用户名或密码，它也会打印Success!。为什么？

#!/usr/bin/perl 

%data = qw(
    javad root 
    ali  1234 
    george password 
); 

print "Please enter your name :\n"; 
$name = <STDIN>; 
chomp($name); 
$pass = $data{$name}; 

#receiving password from user 
#compare it with correct password 
#print the result 
print "What is your password ?\n"; 
$guess = <STDIN>; 
chomp($guess); 

$whileTest = "True"; 
while ($whileTest eq "True") { 
    if ($pass eq $guess) { 
     print "Success!\n"; 
     $whileTest = "False"; 
    } 
    elsif ($pass ne $guess) { 
     print "Wrong password , Try again :\n"; 
     $guess = <STDIN>; 
     chomp($guess); 
    } 
} 

Answer 1

快速修复

$pass = $data{$name} or die "No password for $name"; 

当你输入空白名称，密码是undef后来与空字符串相等于真实的，允许访问。 use warnings;至少会抱怨这种比较。