修改Perl子例程中的变量

sub modify_variable {
    my $variable = shift;  # 接受参数
    $variable = "modified";  # 修改变量
    return $variable;  # 返回修改后的值
}

my $original_variable = "original";
my $modified_variable = modify_variable($original_variable);  # 调用子例程
print $modified_variable;  # 输出 "modified"

sub modify_variable {
    my $variable_ref = shift;  # 接受引用
    $$variable_ref = "modified";  # 通过引用修改变量的值
}

my $original_variable = "original";
modify_variable(\$original_variable);  # 传递变量的引用
print $original_variable;  # 输出 "modified"

our $global_variable = "original";  # 声明全局变量

sub modify_variable {
    $global_variable = "modified";  # 直接修改全局变量的值
}

modify_variable();  # 调用子例程
print $global_variable;  # 输出 "modified"