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法律研究Perl 中的方法覆蓋
您可以在子類中新增額外的函式，也可以在其父類中新增或修改現有方法的功能。它可以按如下方式完成 −
#!/usr/bin/perl
package Employee;
use Person;
use strict;
our @ISA = qw(Person); # inherits from Person
# Override constructor
sub new {
my ($class) = @_;
# Call the constructor of the parent class, Person.
my $self = $class->SUPER::new( $_[1], $_[2], $_[3] );
# Add few more attributes
$self->{_id} = undef;
$self->{_title} = undef;
bless $self, $class;
return $self;
}
# Override helper function
sub getFirstName {
my( $self ) = @_;
# This is child class function.
print "This is child class helper function\n";
return $self->{_firstName};
}
# Add more methods
sub setLastName{
my ( $self, $lastName ) = @_;
$self->{_lastName} = $lastName if defined($lastName);
return $self->{_lastName};
}
sub getLastName {
my( $self ) = @_;
return $self->{_lastName};
}
1;現在讓我們再次嘗試在我們的 main.pl 檔案中使用 Employee 物件並執行它。
#!/usr/bin/perl use Employee; $object = new Employee( "Mohammad", "Saleem", 23234345); # Get first name which is set using constructor. $firstName = $object->getFirstName(); print "Before Setting First Name is : $firstName\n"; # Now Set first name using helper function. $object->setFirstName( "Mohd." ); # Now get first name set by helper function. $firstName = $object->getFirstName(); print "After Setting First Name is : $firstName\n";
當我們執行上述程式時，會產生以下結果 −
First Name is Mohammad Last Name is Saleem SSN is 23234345 This is child class helper function Before Setting First Name is : Mohammad This is child class helper function After Setting First Name is : Mohd.
更新於： 02-Dec-2019
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