View Subcategory
Implement Inheritance Heirarchy
Implement a Shape abstract class which will form the base of an inheritance hierarchy that models 2D geometric shapes. It will have:
* A non-mutable
* A
* A
* A non-mutable
'name' property or data member set by derived or descendant classes at construction time
* A
'area' method intended to be overridden by derived or descendant classes ( double precision floating point return value)
* A
'print' method (also for overriding) will display the shape's name, area, and all shape-specific values
Two derived or descendant classes will be created:
* Circle -> Constructor requires a 'radius' argument, and a 'circumference' method to be implemented
* Rectangle -> Constructor requires 'length' and 'breadth' arguments, and a 'perimeter' method to be implemented
Instantiate an object of each class, and invoke each objects 'print' method to show relevant details.
clojure
(defmulti area :Shape)
(defmulti print :Shape)
; Circle methods
(defn circle [r]
{:Shape :Circle
:name "Circle"
:radius r})
(defn circumference [c]
(* 2 Math/PI (:radius c)))
(defmethod area :Circle [c]
(* Math/PI (:radius c) (:radius c)))
(defmethod print :Circle [c]
(println (format "I am a %s with ->" (:name c)))
(println (format "Radius: %.2f" (:radius c)))
(println (format "Area: %.2f" (area c)))
(println (format "Circumference: %.2f" (circumference c))))
; Rectangle methods
(defn rectangle [l b]
{:Shape :Rectangle
:name "Rectangle"
:length l
:breadth b})
(defn perimeter [r]
(+ (* 2 (:length r)) (* 2 (:breadth r))))
(defmethod area :Rectangle [r]
(* (:length r) (:breadth r)))
(defmethod print :Rectangle [r]
(println (format "I am a %s with ->" (:name r)))
(println (format "Length, Width: %.2f, %.2f" (:length r) (:breadth r)))
(println (format "Area: %.2f" (area r)))
(println (format "Perimeter: %.2f" (perimeter r))))
; usage of the "classes"
(let [shapes (list (circle 4.2) (rectangle 2.7 3.1) (rectangle 6.2 2.6) (circle 17.3))]
(doseq [shape shapes]
(print shape)))
(defmulti print :Shape)
; Circle methods
(defn circle [r]
{:Shape :Circle
:name "Circle"
:radius r})
(defn circumference [c]
(* 2 Math/PI (:radius c)))
(defmethod area :Circle [c]
(* Math/PI (:radius c) (:radius c)))
(defmethod print :Circle [c]
(println (format "I am a %s with ->" (:name c)))
(println (format "Radius: %.2f" (:radius c)))
(println (format "Area: %.2f" (area c)))
(println (format "Circumference: %.2f" (circumference c))))
; Rectangle methods
(defn rectangle [l b]
{:Shape :Rectangle
:name "Rectangle"
:length l
:breadth b})
(defn perimeter [r]
(+ (* 2 (:length r)) (* 2 (:breadth r))))
(defmethod area :Rectangle [r]
(* (:length r) (:breadth r)))
(defmethod print :Rectangle [r]
(println (format "I am a %s with ->" (:name r)))
(println (format "Length, Width: %.2f, %.2f" (:length r) (:breadth r)))
(println (format "Area: %.2f" (area r)))
(println (format "Perimeter: %.2f" (perimeter r))))
; usage of the "classes"
(let [shapes (list (circle 4.2) (rectangle 2.7 3.1) (rectangle 6.2 2.6) (circle 17.3))]
(doseq [shape shapes]
(print shape)))
cpp
#include <string>
#include <iostream>
using namespace std;
static const double PI = 3.141592;
class Shape {
protected:
string name_;
public:
Shape(const string& name) : name_(name) { }
virtual double area() const = 0;
virtual void print() const = 0;
};
class Circle : public Shape {
double radius_;
public:
Circle(double radius) : Shape("circle"), radius_(radius) { }
double area() const {
return PI * radius_ * radius_;
}
void print() const {
cout << "A " << name_ << " with radius " << radius_ << ", area "
<< area() << " and circumference " << circumference() << "."
<< endl;
}
double circumference() const {
return 2 * PI * radius_;
}
};
class Rectangle : public Shape {
double length_;
double breadth_;
public:
Rectangle(double length, double breadth) :
Shape("rectangle"), length_(length), breadth_(breadth) { }
double area() const {
return length_ * breadth_;
}
void print() const {
cout << "A " << name_ << " with length " << length_ << ", breadth "
<< breadth_ << ", area " << area() << " and perimeter "
<< perimeter() << "." << endl;
}
double perimeter() const {
return 2 * length_ + 2 * breadth_;
}
};
int main(int argc, char *argv[])
{
Circle circle(4);
circle.print();
Rectangle rectangle(2, 5.5);
rectangle.print();
}
#include <iostream>
using namespace std;
static const double PI = 3.141592;
class Shape {
protected:
string name_;
public:
Shape(const string& name) : name_(name) { }
virtual double area() const = 0;
virtual void print() const = 0;
};
class Circle : public Shape {
double radius_;
public:
Circle(double radius) : Shape("circle"), radius_(radius) { }
double area() const {
return PI * radius_ * radius_;
}
void print() const {
cout << "A " << name_ << " with radius " << radius_ << ", area "
<< area() << " and circumference " << circumference() << "."
<< endl;
}
double circumference() const {
return 2 * PI * radius_;
}
};
class Rectangle : public Shape {
double length_;
double breadth_;
public:
Rectangle(double length, double breadth) :
Shape("rectangle"), length_(length), breadth_(breadth) { }
double area() const {
return length_ * breadth_;
}
void print() const {
cout << "A " << name_ << " with length " << length_ << ", breadth "
<< breadth_ << ", area " << area() << " and perimeter "
<< perimeter() << "." << endl;
}
double perimeter() const {
return 2 * length_ + 2 * breadth_;
}
};
int main(int argc, char *argv[])
{
Circle circle(4);
circle.print();
Rectangle rectangle(2, 5.5);
rectangle.print();
}
fantom
abstract class Shape
{
const Str name
new make(Str name) { this.name = name }
abstract Float area()
abstract Void print()
}
class Circle : Shape
{
private Float radius
new make(Float radius) : super("circle") { this.radius = radius }
Float circumference() { return 2 * Float.pi * radius }
override Float area() { return Float.pi * radius.pow(2.0f) }
override Void print()
{
echo("I am a $name with radius $radius, area $area
and circumference $circumference")
}
}
class Rectangle : Shape
{
private Float length
private Float breadth
new make(Float length, Float breadth) : super("rectangle")
{
this.length = length
this.breadth = breadth
}
Float perimeter() { return 2 * (length + breadth) }
override Float area() { return length * breadth }
override Void print()
{
echo("I am a $name with length $length, breadth $breadth,
area $area and perimeter $perimeter")
}
}
circle := Circle(4.0f)
circle.print
rectangle := Rectangle(2.0f, 5.5f)
rectangle.print
{
const Str name
new make(Str name) { this.name = name }
abstract Float area()
abstract Void print()
}
class Circle : Shape
{
private Float radius
new make(Float radius) : super("circle") { this.radius = radius }
Float circumference() { return 2 * Float.pi * radius }
override Float area() { return Float.pi * radius.pow(2.0f) }
override Void print()
{
echo("I am a $name with radius $radius, area $area
and circumference $circumference")
}
}
class Rectangle : Shape
{
private Float length
private Float breadth
new make(Float length, Float breadth) : super("rectangle")
{
this.length = length
this.breadth = breadth
}
Float perimeter() { return 2 * (length + breadth) }
override Float area() { return length * breadth }
override Void print()
{
echo("I am a $name with length $length, breadth $breadth,
area $area and perimeter $perimeter")
}
}
circle := Circle(4.0f)
circle.print
rectangle := Rectangle(2.0f, 5.5f)
rectangle.print
fsharp
[<AbstractClass>]
type Shape(name:string) =
member this.Name = name
abstract Area : float
abstract Print : unit -> unit
type Circle(name, radius:float) =
inherit Shape(name)
member this.Radius = radius
member this.Circumference =
System.Math.PI * radius * 2.
override this.Area =
System.Math.PI * radius * radius
override this.Print() =
printfn "Circle: %s" this.Name
printfn "Area: %f" this.Area
printfn "Circumference: %f" this.Circumference
printfn "Radius: %f" this.Radius
type Rectangle(name, length:float, breadth:float) =
inherit Shape(name)
member this.Length = length
member this.Breadth = breadth
member this.Perimiter =
(length * 2.) + (breadth * 2.)
override this.Area =
length * breadth
override this.Print() =
printfn "Rectangle: %s" this.Name
printfn "Area: %f" this.Area
printfn "Perimiter: %f" this.Perimiter
printfn "Length: %f" this.Length
printfn "Breadth: %f" this.Breadth
let c = Circle("Foo", 2.1)
let r = Rectangle("Bar", 2.2, 3.3)
c.Print()
printfn ""
r.Print()
type Shape(name:string) =
member this.Name = name
abstract Area : float
abstract Print : unit -> unit
type Circle(name, radius:float) =
inherit Shape(name)
member this.Radius = radius
member this.Circumference =
System.Math.PI * radius * 2.
override this.Area =
System.Math.PI * radius * radius
override this.Print() =
printfn "Circle: %s" this.Name
printfn "Area: %f" this.Area
printfn "Circumference: %f" this.Circumference
printfn "Radius: %f" this.Radius
type Rectangle(name, length:float, breadth:float) =
inherit Shape(name)
member this.Length = length
member this.Breadth = breadth
member this.Perimiter =
(length * 2.) + (breadth * 2.)
override this.Area =
length * breadth
override this.Print() =
printfn "Rectangle: %s" this.Name
printfn "Area: %f" this.Area
printfn "Perimiter: %f" this.Perimiter
printfn "Length: %f" this.Length
printfn "Breadth: %f" this.Breadth
let c = Circle("Foo", 2.1)
let r = Rectangle("Bar", 2.2, 3.3)
c.Print()
printfn ""
r.Print()
groovy
abstract class Shape {
final name
Shape(name) { this.name = name }
abstract area()
abstract print()
}
class Circle extends Shape {
final radius
Circle(radius) {
super('circle')
this.radius = radius
}
def area() { Math.PI * radius * radius }
def circumference() { 2 * Math.PI * radius }
def print() {
println "I am a $name with ->"
printf 'Radius: %.2f\n', radius
printf 'Area: %.2f\n', area()
printf 'Circumference: %.2f\n', circumference()
}
}
class Rectangle extends Shape {
final length, breadth
def Rectangle(length, breadth) {
super("rectangle")
this.length = length
this.breadth = breadth
}
def area() { length * breadth }
def perimeter() { 2 * length + 2 * breadth }
def print() {
println "I am a $name with ->"
printf 'Length, Width: %.2f, %.2f\n', length, breadth
printf 'Area: %.2f\n', area()
printf 'Perimeter: %.2f\n', perimeter()
}
}
shapes = [new Circle(4.2), new Rectangle(2.7, 3.1), new Rectangle(6.2, 2.6), new Circle(17.3)]
shapes.each { shape -> shape.print() }
final name
Shape(name) { this.name = name }
abstract area()
abstract print()
}
class Circle extends Shape {
final radius
Circle(radius) {
super('circle')
this.radius = radius
}
def area() { Math.PI * radius * radius }
def circumference() { 2 * Math.PI * radius }
def print() {
println "I am a $name with ->"
printf 'Radius: %.2f\n', radius
printf 'Area: %.2f\n', area()
printf 'Circumference: %.2f\n', circumference()
}
}
class Rectangle extends Shape {
final length, breadth
def Rectangle(length, breadth) {
super("rectangle")
this.length = length
this.breadth = breadth
}
def area() { length * breadth }
def perimeter() { 2 * length + 2 * breadth }
def print() {
println "I am a $name with ->"
printf 'Length, Width: %.2f, %.2f\n', length, breadth
printf 'Area: %.2f\n', area()
printf 'Perimeter: %.2f\n', perimeter()
}
}
shapes = [new Circle(4.2), new Rectangle(2.7, 3.1), new Rectangle(6.2, 2.6), new Circle(17.3)]
shapes.each { shape -> shape.print() }
haskell
data Circle = C { namec :: String, radius :: Float }
data Rectangle = R { namer :: String, len :: Float, breadth :: Float }
circumference (C _ r) = 2 * pi * r
perimeter (R _ l b) = 2 * (l + b)
class Shape a where
area :: a -> Float
name :: a -> String
println :: a -> IO ()
instance Shape Circle where
area (C _ r) = pi * r * r
println c = print $ namec c ++ " : area = " ++
show (area c) ++ ", radius = " ++
show (radius c)
name (C n _) = n
instance Shape Rectangle where
area (R _ l b) = l * b
println r = print $ namer r ++ " : area = " ++
show (area r) ++ ", length = " ++
show (len r) ++ ", breadth = " ++
show (breadth r)
name (R n _ _) = n
main = do
let c = C { namec = "Circle", radius = 2.34 }
r = R { namer = "Rectangle", len = 3.4, breadth = 2.456 }
println c
println r
data Rectangle = R { namer :: String, len :: Float, breadth :: Float }
circumference (C _ r) = 2 * pi * r
perimeter (R _ l b) = 2 * (l + b)
class Shape a where
area :: a -> Float
name :: a -> String
println :: a -> IO ()
instance Shape Circle where
area (C _ r) = pi * r * r
println c = print $ namec c ++ " : area = " ++
show (area c) ++ ", radius = " ++
show (radius c)
name (C n _) = n
instance Shape Rectangle where
area (R _ l b) = l * b
println r = print $ namer r ++ " : area = " ++
show (area r) ++ ", length = " ++
show (len r) ++ ", breadth = " ++
show (breadth r)
name (R n _ _) = n
main = do
let c = C { namec = "Circle", radius = 2.34 }
r = R { namer = "Rectangle", len = 3.4, breadth = 2.456 }
println c
println r
java
/*
* Will work with version 1.4 if you remove the @Override annotation
* and declare floating point numbers using the primitive "double"
*/
abstract class Shape {
protected final String name;
public Shape(String name) {
this.name = name;
}
public abstract Double area();
public abstract void print();
}
class Circle extends Shape {
private Double radius;
public Circle(Double radius) {
super("circle");
this.radius = radius;
}
@Override
public Double area() {
return Math.PI * Math.pow(radius, 2);
}
@Override
public void print() {
System.out.println("A " + name + " with radius " + radius
+ ", area " + area() + " and circumference "
+ circumference() + ".");
}
public Double circumference() {
return 2 * Math.PI * radius;
}
}
class Rectangle extends Shape {
private Double length, breadth;
public Rectangle(Double length, Double breadth) {
super("Rectangle");
this.length = length;
this.breadth = breadth;
}
@Override
public Double area() {
return length * breadth;
}
public Double perimeter() {
return 2 * length + 2 * breadth;
}
@Override
public void print() {
System.out.println("A " + name + " with length " + length
+ ", breadth " + breadth + ", area " + area()
+ " and perimeter " + perimeter() + ".");
}
}
Circle circle = new Circle(4d);
circle.print();
Rectangle rectangle = new Rectangle(2d, 5.5);
rectangle.print();
* Will work with version 1.4 if you remove the @Override annotation
* and declare floating point numbers using the primitive "double"
*/
abstract class Shape {
protected final String name;
public Shape(String name) {
this.name = name;
}
public abstract Double area();
public abstract void print();
}
class Circle extends Shape {
private Double radius;
public Circle(Double radius) {
super("circle");
this.radius = radius;
}
@Override
public Double area() {
return Math.PI * Math.pow(radius, 2);
}
@Override
public void print() {
System.out.println("A " + name + " with radius " + radius
+ ", area " + area() + " and circumference "
+ circumference() + ".");
}
public Double circumference() {
return 2 * Math.PI * radius;
}
}
class Rectangle extends Shape {
private Double length, breadth;
public Rectangle(Double length, Double breadth) {
super("Rectangle");
this.length = length;
this.breadth = breadth;
}
@Override
public Double area() {
return length * breadth;
}
public Double perimeter() {
return 2 * length + 2 * breadth;
}
@Override
public void print() {
System.out.println("A " + name + " with length " + length
+ ", breadth " + breadth + ", area " + area()
+ " and perimeter " + perimeter() + ".");
}
}
Circle circle = new Circle(4d);
circle.print();
Rectangle rectangle = new Rectangle(2d, 5.5);
rectangle.print();
ocaml
class virtual shape =
object(self)
method name = "shape"
method virtual area : float
method print = Printf.sprintf "%s, area %f" self#name self#area
end ;;
let pi = 4. *. atan 1.
class circle radius =
object(self)
inherit shape as super
method name = "circle"
method area = radius *. radius *. pi
method circumference = radius *. 2. *. pi
method print = Printf.sprintf "%s, circumference %f" super#print self#circumference
end
class rectangle length breadth =
object(self)
inherit shape as super
method name = "rectangle"
method area = length *. breadth
method perimeter = 2. *. ( length +. breadth)
method print = Printf.sprintf "%s, perimeter %f" super#print self#perimeter
end
let c = new circle 5. in
let r = new rectangle 7. 3. in
print_endline c#print;
print_endline r#print
object(self)
method name = "shape"
method virtual area : float
method print = Printf.sprintf "%s, area %f" self#name self#area
end ;;
let pi = 4. *. atan 1.
class circle radius =
object(self)
inherit shape as super
method name = "circle"
method area = radius *. radius *. pi
method circumference = radius *. 2. *. pi
method print = Printf.sprintf "%s, circumference %f" super#print self#circumference
end
class rectangle length breadth =
object(self)
inherit shape as super
method name = "rectangle"
method area = length *. breadth
method perimeter = 2. *. ( length +. breadth)
method print = Printf.sprintf "%s, perimeter %f" super#print self#perimeter
end
let c = new circle 5. in
let r = new rectangle 7. 3. in
print_endline c#print;
print_endline r#print
perl
package Shapes;
use MooseX::Declare;
class Shape {
use MooseX::ABC;
requires qw/area print/;
has 'name' => (is => 'ro', isa => 'Str', default => '', required => 0, init_arg => undef );
}
class Circle extends Shape {
use constant PI => 4 * atan2(1, 1);
has '+name' => ( default => 'circle' );
has 'radius' => (is => 'ro', isa => 'Num', required => 1, init_arg => 'r' );
sub area { PI * ( $_[0]->radius ** 2 ) }
sub circumference { 2 * PI * ( $_[0]->radius ** 2 ) }
sub print {
my $self = shift;
printf <<"END_OF_BLOCK", map { $self->$_ } qw/name radius area circumference/;
I am a '%s' with
Radius: %.2f
Area: %.2f
Circumference: %.2f
END_OF_BLOCK
}
}
class Rectangle extends Shape {
has '+name' => ( default => 'rectangle' );
has 'length' => (is => 'ro', isa => 'Num', required => 1, init_arg => 'l' );
has 'breadth' => (is => 'ro', isa => 'Num', required => 1, init_arg => 'b' );
sub area { $_[0]->length * $_[0]->breadth }
sub perimeter { 2 * ( $_[0]->length + $_[0]->breadth ) }
sub print {
my $self = shift;
printf <<"END_OF_BLOCK", map { $self->$_ } qw/name length breadth area perimeter/;
I am a '%s' with
Length, Width: %.2f, %.2f
Area: %.2f
Perimeter: %.2f
END_OF_BLOCK
}
}
1;
package main;
my @shapes = ( Circle->new( r => 4.2 ), Rectangle->new(l => 2.7, b => 3.1),
Rectangle->new(l => 6.2, b => 2.6), Circle->new( r => 17.3) );
$_->print for @shapes;
use MooseX::Declare;
class Shape {
use MooseX::ABC;
requires qw/area print/;
has 'name' => (is => 'ro', isa => 'Str', default => '', required => 0, init_arg => undef );
}
class Circle extends Shape {
use constant PI => 4 * atan2(1, 1);
has '+name' => ( default => 'circle' );
has 'radius' => (is => 'ro', isa => 'Num', required => 1, init_arg => 'r' );
sub area { PI * ( $_[0]->radius ** 2 ) }
sub circumference { 2 * PI * ( $_[0]->radius ** 2 ) }
sub print {
my $self = shift;
printf <<"END_OF_BLOCK", map { $self->$_ } qw/name radius area circumference/;
I am a '%s' with
Radius: %.2f
Area: %.2f
Circumference: %.2f
END_OF_BLOCK
}
}
class Rectangle extends Shape {
has '+name' => ( default => 'rectangle' );
has 'length' => (is => 'ro', isa => 'Num', required => 1, init_arg => 'l' );
has 'breadth' => (is => 'ro', isa => 'Num', required => 1, init_arg => 'b' );
sub area { $_[0]->length * $_[0]->breadth }
sub perimeter { 2 * ( $_[0]->length + $_[0]->breadth ) }
sub print {
my $self = shift;
printf <<"END_OF_BLOCK", map { $self->$_ } qw/name length breadth area perimeter/;
I am a '%s' with
Length, Width: %.2f, %.2f
Area: %.2f
Perimeter: %.2f
END_OF_BLOCK
}
}
1;
package main;
my @shapes = ( Circle->new( r => 4.2 ), Rectangle->new(l => 2.7, b => 3.1),
Rectangle->new(l => 6.2, b => 2.6), Circle->new( r => 17.3) );
$_->print for @shapes;
{
package Shapes;
sub new {
my $class = shift;
die 'Invalid parameters' if (@_ % 2);
my %parameters = @_;
die 'Missing name' unless defined $parameters{name};
bless \%parameters, $class
}
sub area {
die
'area() method must be implemented by ',__PACKAGE__.' subclasses';
}
sub print {
my $self = shift;
printf "Name: \t%s\n", $self->{name};
printf "Area: \t%.2f\n", $self->area();
}
}
{
package Circle;
use parent -norequire, 'Shapes';
use Scalar::Util qw/looks_like_number/;
use Math::Trig;
sub new {
my $class = shift;
my $self = $class->SUPER::new(name => 'Circle', @_);
die 'Missing radius' unless defined($self->{radius});
die 'Invalid radius (not a number)'
unless looks_like_number($self->{radius});
$self
}
sub area {
my $self = shift;
pi * ($self->{radius} ** 2)
}
sub circumference {
my $self = shift;
2 * pi * $self->{radius};
}
sub print {
my $self = shift;
$self->SUPER::print;
printf "Circumference: \t%.2f\n", $self->circumference;
}
}
{
package Rectangle;
use parent -norequire, 'Shapes';
use Scalar::Util qw/looks_like_number/;
sub new {
my $class = shift;
my $self = $class->SUPER::new(name => 'Rectangle', @_);
do {
die "Missing $_" unless defined($self->{$_});
die "Invalid $_" unless looks_like_number($self->{$_});
} for qw/length breadth/;
$self;
}
sub area {
my $self = shift;
$self->{length} * $self->{breadth}
}
sub print {
my $self = shift;
$self->SUPER::print();
do {
printf ucfirst($_).": \t%.2f\n", $self->{$_}
} for qw/length breadth/;
}
}
package main;
my @shapes = ( Circle->new( radius => 4.2 ),
Rectangle->new(length => 2.7, breadth => 3.1),
Rectangle->new(length => 6.2, breadth => 2.6),
Circle->new( radius => 17.3) );
$_->print for @shapes;
package Shapes;
sub new {
my $class = shift;
die 'Invalid parameters' if (@_ % 2);
my %parameters = @_;
die 'Missing name' unless defined $parameters{name};
bless \%parameters, $class
}
sub area {
die
'area() method must be implemented by ',__PACKAGE__.' subclasses';
}
sub print {
my $self = shift;
printf "Name: \t%s\n", $self->{name};
printf "Area: \t%.2f\n", $self->area();
}
}
{
package Circle;
use parent -norequire, 'Shapes';
use Scalar::Util qw/looks_like_number/;
use Math::Trig;
sub new {
my $class = shift;
my $self = $class->SUPER::new(name => 'Circle', @_);
die 'Missing radius' unless defined($self->{radius});
die 'Invalid radius (not a number)'
unless looks_like_number($self->{radius});
$self
}
sub area {
my $self = shift;
pi * ($self->{radius} ** 2)
}
sub circumference {
my $self = shift;
2 * pi * $self->{radius};
}
sub print {
my $self = shift;
$self->SUPER::print;
printf "Circumference: \t%.2f\n", $self->circumference;
}
}
{
package Rectangle;
use parent -norequire, 'Shapes';
use Scalar::Util qw/looks_like_number/;
sub new {
my $class = shift;
my $self = $class->SUPER::new(name => 'Rectangle', @_);
do {
die "Missing $_" unless defined($self->{$_});
die "Invalid $_" unless looks_like_number($self->{$_});
} for qw/length breadth/;
$self;
}
sub area {
my $self = shift;
$self->{length} * $self->{breadth}
}
sub print {
my $self = shift;
$self->SUPER::print();
do {
printf ucfirst($_).": \t%.2f\n", $self->{$_}
} for qw/length breadth/;
}
}
package main;
my @shapes = ( Circle->new( radius => 4.2 ),
Rectangle->new(length => 2.7, breadth => 3.1),
Rectangle->new(length => 6.2, breadth => 2.6),
Circle->new( radius => 17.3) );
$_->print for @shapes;
php
<?php
abstract class Shape
{
protected $name;
abstract public function area ();
abstract public function _print ();
public function __construct ($name)
{
$this->name = $name;
}
}
class Circle extends Shape
{
protected $radius;
public function __construct ($radius)
{
parent::__construct('Circle');
$this->radius = $radius;
}
public function area ()
{
return pi() * $this->radius * $this->radius;
}
public function circumference ()
{
return 2 * pi() * $this->radius;
}
public function _print ()
{
print("I am a {$this->name} with ->\n");
print(" Radius: {$this->radius}\n");
print(" Area: {$this->area()}\n");
print(" Circumference {$this->circumference()}\n");
}
}
class Rectangle extends Shape
{
protected $length;
protected $breadth;
public function __construct ($length, $breadth)
{
parent::__construct('Rectangle');
$this->length = $length;
$this->breadth = $breadth;
}
public function area ()
{
return $this->length * $this->breadth;
}
public function perimeter ()
{
return (2 * $this->length) + (2 * $this->breadth);
}
public function _print ()
{
print("I am a {$this->name} with ->\n");
print(" Length, Width: {$this->length}, {$this->breadth}\n");
print(" Area: {$this->area()}\n");
print(" Perimeter: {$this->perimeter()}\n");
}
}
$shapes = array(new Circle(4.2) , new Rectangle(2.7, 3.1) , new Rectangle(6.2, 2.6) , new Circle(17.3));
foreach ($shapes as $shape) {
$shape->_print();
}
abstract class Shape
{
protected $name;
abstract public function area ();
abstract public function _print ();
public function __construct ($name)
{
$this->name = $name;
}
}
class Circle extends Shape
{
protected $radius;
public function __construct ($radius)
{
parent::__construct('Circle');
$this->radius = $radius;
}
public function area ()
{
return pi() * $this->radius * $this->radius;
}
public function circumference ()
{
return 2 * pi() * $this->radius;
}
public function _print ()
{
print("I am a {$this->name} with ->\n");
print(" Radius: {$this->radius}\n");
print(" Area: {$this->area()}\n");
print(" Circumference {$this->circumference()}\n");
}
}
class Rectangle extends Shape
{
protected $length;
protected $breadth;
public function __construct ($length, $breadth)
{
parent::__construct('Rectangle');
$this->length = $length;
$this->breadth = $breadth;
}
public function area ()
{
return $this->length * $this->breadth;
}
public function perimeter ()
{
return (2 * $this->length) + (2 * $this->breadth);
}
public function _print ()
{
print("I am a {$this->name} with ->\n");
print(" Length, Width: {$this->length}, {$this->breadth}\n");
print(" Area: {$this->area()}\n");
print(" Perimeter: {$this->perimeter()}\n");
}
}
$shapes = array(new Circle(4.2) , new Rectangle(2.7, 3.1) , new Rectangle(6.2, 2.6) , new Circle(17.3));
foreach ($shapes as $shape) {
$shape->_print();
}
python
#Start with the import statements.
import math # necessary to get the value of pi
class Shape(object):
"""Shape Class"""
def __init__(self):
"""Constructor method"""
pass #Do nothing here
def area(self):
"""The area method"""
pass #Do nothing here
def print_(self):
"""
The print method. Note the trailing underscore - this is because
there is a reserved statement called 'print' in python 2.x. The
trailing underscore is the accepted method of re-using names without
rebinding them
"""
print 'The name is: %s' % self.name #Print the only property we currently have
def _getName(self):
"""The getter method for the 'name' property.
Note that getter methods are generally discouraged in python"""
return self._name
_name = None # The leading underscore gives a weak non-public value
# to a variable. Two leading underscores will mangle its
# name at runtime, to make it more difficult to access.
# Note there is no real 'private' variable type in python.
name = property(_getName, doc='The name of this object')
# property statements work like: property(fget=None, fset=None, fdel=None, doc=None)
class Circle(Shape):
"""Circle Class - a sub class of shape"""
def __init__(self, radius, name='Circle'):
"""Constructor method again"""
Shape.__init__(self) # init the super class
self.radius = radius # Store the radius
self._setCircumference()# Function call
self._name = name
def _setCircumference(self):
self.circumference = 2*math.pi*self.radius
def area(self):
'''Return the area of this circle'''
tmpAera = math.pi * self.radius**2
return tmpAera
def print_(self):
'''The print method'''
super(Circle, self).print_() # This calls the print_ method in
# the super classes of Circle, in
# this case Shape
print 'The radius is: %f' % self.radius
print 'The circumference is %f' % self.circumference
print 'The area is: %f' % self.area()
class Rectangle(Shape):
"""The Rectangle Class"""
def __init__(self, length, breadth, name='Rectangle'):
Shape.__init__(self)
self._name = name
self.length = length
self.breadth = breadth
self.perimeter()
def area(self):
return self.breadth*self.length
def perimeter(self):
self._perimeter = self.breadth*2+self.length*2
return self._perimeter # You have a method return a value and still
# safely call it without handling the return
# value. This would be collected by garbage
# collection.
def print_(self):
super(Rectangle, self).print_()
print 'The length is %f and the breadth is %f' %(self.length, self.breadth)
print 'The perimeter is: %f' %self._perimeter
print 'The area is: %f' % self.area()
if __name__ == '__main__':
rectangle = Rectangle(5,3)
circle = Circle(5, name='Round and Round')
rectangle.print_()
circle.print_()
import math # necessary to get the value of pi
class Shape(object):
"""Shape Class"""
def __init__(self):
"""Constructor method"""
pass #Do nothing here
def area(self):
"""The area method"""
pass #Do nothing here
def print_(self):
"""
The print method. Note the trailing underscore - this is because
there is a reserved statement called 'print' in python 2.x. The
trailing underscore is the accepted method of re-using names without
rebinding them
"""
print 'The name is: %s' % self.name #Print the only property we currently have
def _getName(self):
"""The getter method for the 'name' property.
Note that getter methods are generally discouraged in python"""
return self._name
_name = None # The leading underscore gives a weak non-public value
# to a variable. Two leading underscores will mangle its
# name at runtime, to make it more difficult to access.
# Note there is no real 'private' variable type in python.
name = property(_getName, doc='The name of this object')
# property statements work like: property(fget=None, fset=None, fdel=None, doc=None)
class Circle(Shape):
"""Circle Class - a sub class of shape"""
def __init__(self, radius, name='Circle'):
"""Constructor method again"""
Shape.__init__(self) # init the super class
self.radius = radius # Store the radius
self._setCircumference()# Function call
self._name = name
def _setCircumference(self):
self.circumference = 2*math.pi*self.radius
def area(self):
'''Return the area of this circle'''
tmpAera = math.pi * self.radius**2
return tmpAera
def print_(self):
'''The print method'''
super(Circle, self).print_() # This calls the print_ method in
# the super classes of Circle, in
# this case Shape
print 'The radius is: %f' % self.radius
print 'The circumference is %f' % self.circumference
print 'The area is: %f' % self.area()
class Rectangle(Shape):
"""The Rectangle Class"""
def __init__(self, length, breadth, name='Rectangle'):
Shape.__init__(self)
self._name = name
self.length = length
self.breadth = breadth
self.perimeter()
def area(self):
return self.breadth*self.length
def perimeter(self):
self._perimeter = self.breadth*2+self.length*2
return self._perimeter # You have a method return a value and still
# safely call it without handling the return
# value. This would be collected by garbage
# collection.
def print_(self):
super(Rectangle, self).print_()
print 'The length is %f and the breadth is %f' %(self.length, self.breadth)
print 'The perimeter is: %f' %self._perimeter
print 'The area is: %f' % self.area()
if __name__ == '__main__':
rectangle = Rectangle(5,3)
circle = Circle(5, name='Round and Round')
rectangle.print_()
circle.print_()
ruby
class Shape
def initialize(name="") @name = name end
end
class Circle < Shape
def initialize(radius) super("circle") ; @radius = radius end
def area() 3.14159 * @radius * @radius end
def circumference() 2 * 3.14159 * @radius end
def print()
puts "I am a #{@name} with ->"
puts "Radius: %.2f" % @radius
puts "Area: %.2f" % self.area()
puts "Circumference: %.2f\n" % self.circumference()
end
end
class Rectangle < Shape
def initialize(length, breadth) super("rectangle") ; @length = length ; @breadth = breadth end
def area() @length * @breadth end
def perimeter() 2 * @length + 2 * @breadth end
def print()
puts "I am a #{@name} with ->"
printf("Length, Width: %.2f, %.2f\n", @length, @breadth)
puts "Area: %.2f" % self.area()
puts "Perimeter: %.2f\n" % self.perimeter()
end
end
# ------
shapes = [Circle.new(4.2), Rectangle.new(2.7, 3.1), Rectangle.new(6.2, 2.6), Circle.new(17.3)]
shapes.each {|shape| shape.print}
def initialize(name="") @name = name end
end
class Circle < Shape
def initialize(radius) super("circle") ; @radius = radius end
def area() 3.14159 * @radius * @radius end
def circumference() 2 * 3.14159 * @radius end
def print()
puts "I am a #{@name} with ->"
puts "Radius: %.2f" % @radius
puts "Area: %.2f" % self.area()
puts "Circumference: %.2f\n" % self.circumference()
end
end
class Rectangle < Shape
def initialize(length, breadth) super("rectangle") ; @length = length ; @breadth = breadth end
def area() @length * @breadth end
def perimeter() 2 * @length + 2 * @breadth end
def print()
puts "I am a #{@name} with ->"
printf("Length, Width: %.2f, %.2f\n", @length, @breadth)
puts "Area: %.2f" % self.area()
puts "Perimeter: %.2f\n" % self.perimeter()
end
end
# ------
shapes = [Circle.new(4.2), Rectangle.new(2.7, 3.1), Rectangle.new(6.2, 2.6), Circle.new(17.3)]
shapes.each {|shape| shape.print}
scala
abstract class Shape (val name: String) {
def area : Double
def print()
}
class Circle (val radius: Double) extends Shape("Circle") {
def area = Math.Pi * radius * radius
def circumference = 2 * Math.Pi * radius
def print() {
println("I'm a " + name + " with")
printf(" * radius = %.2f\n", radius)
printf(" * area = %.2f\n", area)
printf(" * circumference = %.2f\n\n", circumference)
}
}
class Rectangle (val length: Double, val breadth: Double) extends Shape("Rectangle") {
def area = length * breadth
def perimeter = 2 * (length + breadth)
def print() {
println("I'm a " + name + " with")
printf(" * length = %.2f\n", length)
printf(" * breadth = %.2f\n", breadth)
printf(" * area = %.2f\n", area)
printf(" * perimeter = %.2f\n\n", perimeter)
}
}
val shapes = List(new Circle(5.4), new Rectangle(7.8, 6.5))
shapes foreach (_.print)
def area : Double
def print()
}
class Circle (val radius: Double) extends Shape("Circle") {
def area = Math.Pi * radius * radius
def circumference = 2 * Math.Pi * radius
def print() {
println("I'm a " + name + " with")
printf(" * radius = %.2f\n", radius)
printf(" * area = %.2f\n", area)
printf(" * circumference = %.2f\n\n", circumference)
}
}
class Rectangle (val length: Double, val breadth: Double) extends Shape("Rectangle") {
def area = length * breadth
def perimeter = 2 * (length + breadth)
def print() {
println("I'm a " + name + " with")
printf(" * length = %.2f\n", length)
printf(" * breadth = %.2f\n", breadth)
printf(" * area = %.2f\n", area)
printf(" * perimeter = %.2f\n\n", perimeter)
}
}
val shapes = List(new Circle(5.4), new Rectangle(7.8, 6.5))
shapes foreach (_.print)
Implement and use an Interface
Create a Serializable interface consisting of
* Accept a stream or handle or descriptor argument for the source or destination
* Save to destination or restore from source the properties or data members of the implementing class (restrict yourself to the primitive types
Next, create a Person class which has
'save' and 'restore' methods, each of which:
* Accept a stream or handle or descriptor argument for the source or destination
* Save to destination or restore from source the properties or data members of the implementing class (restrict yourself to the primitive types
'int' and 'string')
Next, create a Person class which has
'name' and 'age' properties or data members and implements this interface. Instantiate a Person object, save it to a serial stream, and instantiate a new Person object by restoring it from the serial stream.
clojure
(defn person [name age]
{:name name :age age})
(defn show [p]
(println (format "Name=%s Age=%d" (:name p) (:age p))))
(defn save [p filename]
(with-out-writer filename (pr p)))
(defn restore [filename]
(read (PushbackReader. (reader filename))))
(let [p (person "Ken" 38)]
(show p)
(save p *person-fn*))
(let [ser-p (restore *person-fn*)]
(show ser-p))
{:name name :age age})
(defn show [p]
(println (format "Name=%s Age=%d" (:name p) (:age p))))
(defn save [p filename]
(with-out-writer filename (pr p)))
(defn restore [filename]
(read (PushbackReader. (reader filename))))
(let [p (person "Ken" 38)]
(show p)
(save p *person-fn*))
(let [ser-p (restore *person-fn*)]
(show ser-p))
cpp
struct person
{
person(){}
person(const string &name, int age) : name_(name), age_(age) {}
string name_;
int age_;
template<typename Archive>
void serialize(Archive &ar, const unsigned int version) {
ar & name_ & age_;
}
};
int main()
{
const char *fn = "filename.txt";
person k("Ken", 38);
{
ofstream ofs(fn);
archive::text_oarchive oa(ofs);
oa << k;
}
person restored_person;
{
ifstream ifs(fn);
archive::text_iarchive ia(ifs);
ia >> restored_person;
}
cout << "Name : " << restored_person.name_ << endl
<< "Age : " << restored_person.age_ << endl;
}
{
person(){}
person(const string &name, int age) : name_(name), age_(age) {}
string name_;
int age_;
template<typename Archive>
void serialize(Archive &ar, const unsigned int version) {
ar & name_ & age_;
}
};
int main()
{
const char *fn = "filename.txt";
person k("Ken", 38);
{
ofstream ofs(fn);
archive::text_oarchive oa(ofs);
oa << k;
}
person restored_person;
{
ifstream ifs(fn);
archive::text_iarchive ia(ifs);
ia >> restored_person;
}
cout << "Name : " << restored_person.name_ << endl
<< "Age : " << restored_person.age_ << endl;
}
fantom
@Serializable
class Person
{
Str name
Int age
new make(|This| f) { f(this) }
}
person := Person() { name="Tom Bones"; age=23 }
File(`tommy.dump`).out.writeObj(person).close
Person tom := File(`tommy.dump`).in.readObj
class Person
{
Str name
Int age
new make(|This| f) { f(this) }
}
person := Person() { name="Tom Bones"; age=23 }
File(`tommy.dump`).out.writeObj(person).close
Person tom := File(`tommy.dump`).in.readObj
fsharp
// Since everyone else is using built-in functionality instead of
// defining an interface as required, I won't buck the trend.
// Maybe this problem should be named "Use serialization features" instead
// of "Implement and use an Interface"
open System
open System.IO
open System.Runtime.Serialization.Formatters.Binary
[<Serializable>]
type Person(name:string, age:int) =
member this.Name = name
member this.Age = age
let serialize x =
use ms = new MemoryStream()
let bf = new BinaryFormatter()
bf.Serialize(ms, x)
ms.ToArray()
let deserialize<'a> bytes =
use ms = new MemoryStream(bytes:byte[])
let bf = new BinaryFormatter()
bf.Deserialize(ms) :?> 'a
let before = Person("Joel", 35)
let bytes = serialize before
let after = deserialize<Person> bytes
printfn "Before: %s, %i" before.Name before.Age
printfn "After: %s, %i" after.Name after.Age
// defining an interface as required, I won't buck the trend.
// Maybe this problem should be named "Use serialization features" instead
// of "Implement and use an Interface"
open System
open System.IO
open System.Runtime.Serialization.Formatters.Binary
[<Serializable>]
type Person(name:string, age:int) =
member this.Name = name
member this.Age = age
let serialize x =
use ms = new MemoryStream()
let bf = new BinaryFormatter()
bf.Serialize(ms, x)
ms.ToArray()
let deserialize<'a> bytes =
use ms = new MemoryStream(bytes:byte[])
let bf = new BinaryFormatter()
bf.Deserialize(ms) :?> 'a
let before = Person("Joel", 35)
let bytes = serialize before
let after = deserialize<Person> bytes
printfn "Before: %s, %i" before.Name before.Age
printfn "After: %s, %i" after.Name after.Age
groovy
// Built-in functionality but with slightly different names. Showing usage:
class Person implements Serializable { String name; int age }
p1 = new Person(name:'John', age:21)
p2 = null
output = new ByteArrayOutputStream() // or FileOutputStream, etc.
output.withObjectOutputStream { oos -> oos << p1 }
input = new ByteArrayInputStream(output.toByteArray())
input.withObjectInputStream(getClass().classLoader){ ois -> p2 = ois.readObject() }
assert p2.name == 'John'
assert p2.age == 21
class Person implements Serializable { String name; int age }
p1 = new Person(name:'John', age:21)
p2 = null
output = new ByteArrayOutputStream() // or FileOutputStream, etc.
output.withObjectOutputStream { oos -> oos << p1 }
input = new ByteArrayInputStream(output.toByteArray())
input.withObjectInputStream(getClass().classLoader){ ois -> p2 = ois.readObject() }
assert p2.name == 'John'
assert p2.age == 21
haskell
import Data.Binary
import Control.Monad (liftM2)
data People = People { name :: String, age :: Integer }
deriving (Eq, Show)
class Serializable a where
save :: FilePath -> a -> IO ()
restore :: FilePath -> IO a
instance Serializable People where
save = encodeFile
restore = decodeFile
instance Binary People where
put (People n a) = put n >> put a
get = liftM2 People get get
main = do let fp = "people.dat"
p = People { name = "Joe", age = 24 }
save fp p
p' <- restore fp
print (p' :: People)
import Control.Monad (liftM2)
data People = People { name :: String, age :: Integer }
deriving (Eq, Show)
class Serializable a where
save :: FilePath -> a -> IO ()
restore :: FilePath -> IO a
instance Serializable People where
save = encodeFile
restore = decodeFile
instance Binary People where
put (People n a) = put n >> put a
get = liftM2 People get get
main = do let fp = "people.dat"
p = People { name = "Joe", age = 24 }
save fp p
p' <- restore fp
print (p' :: People)
java
// Serialization to a file
class Person implements Serializable {
private static final long serialVersionUID = 1L;
private String name;
private int age;
public void setAge(int age) {
this.age = age;
}
public int getAge() {
return age;
}
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
public boolean equals(Object obj) {
if(obj == this) return true;
if(obj instanceof Person) {
Person p = (Person) obj;
return (p.getName().equals(this.getName())
& p.getAge() == this.getAge());
}
return false;
}
public String toString() {
return "Name: " + name + ", age: " + age;
}
}
Person person = new Person();
person.setName("Gaylord Focker");
person.setAge(21);
try {
File file = new File("ser.obj");
FileOutputStream fos = new FileOutputStream(file);
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(person);
oos.close();
FileInputStream fis = new FileInputStream(file);
ObjectInputStream ois = new ObjectInputStream(fis);
Person deserializedPerson = (Person) ois.readObject();
ois.close();
System.out.println(deserializedPerson);
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
class Person implements Serializable {
private static final long serialVersionUID = 1L;
private String name;
private int age;
public void setAge(int age) {
this.age = age;
}
public int getAge() {
return age;
}
public void setName(String name) {
this.name = name;
}
public String getName() {
return name;
}
public boolean equals(Object obj) {
if(obj == this) return true;
if(obj instanceof Person) {
Person p = (Person) obj;
return (p.getName().equals(this.getName())
& p.getAge() == this.getAge());
}
return false;
}
public String toString() {
return "Name: " + name + ", age: " + age;
}
}
Person person = new Person();
person.setName("Gaylord Focker");
person.setAge(21);
try {
File file = new File("ser.obj");
FileOutputStream fos = new FileOutputStream(file);
ObjectOutputStream oos = new ObjectOutputStream(fos);
oos.writeObject(person);
oos.close();
FileInputStream fis = new FileInputStream(file);
ObjectInputStream ois = new ObjectInputStream(fis);
Person deserializedPerson = (Person) ois.readObject();
ois.close();
System.out.println(deserializedPerson);
} catch (IOException e) {
e.printStackTrace();
} catch (ClassNotFoundException e) {
e.printStackTrace();
}
ocaml
(* in OCaml, interfaces are class types, and have nothing to do with inheritance,
so I'm not sure what's the correct answer to this problem (if any) *)
class type serializable =
object
method save: out_channel -> unit
method restore: in_channel -> unit
end
class person name age =
object
val mutable my_name = name
val mutable my_age = age
method save oc = output_value oc my_name; output_value oc my_age
method restore ic = my_name <- input_value ic; my_age <- input_value ic
method print = Printf.printf "I'm %s, %d\n" my_name my_age
end
let transfer (o1: serializable) (o2: serializable) =
let temp_filename = "_person" in
let backing_store_save = open_out_bin temp_filename in
o1#save backing_store_save;
close_out backing_store_save;
let backing_store_restore = open_in_bin temp_filename in
o2#restore backing_store_restore;
close_in backing_store_restore
let o = new person "john" 42 in
let o2 = new person "nobody" 0 in
transfer (o :> serializable) (o2 :> serializable);
o2#print
so I'm not sure what's the correct answer to this problem (if any) *)
class type serializable =
object
method save: out_channel -> unit
method restore: in_channel -> unit
end
class person name age =
object
val mutable my_name = name
val mutable my_age = age
method save oc = output_value oc my_name; output_value oc my_age
method restore ic = my_name <- input_value ic; my_age <- input_value ic
method print = Printf.printf "I'm %s, %d\n" my_name my_age
end
let transfer (o1: serializable) (o2: serializable) =
let temp_filename = "_person" in
let backing_store_save = open_out_bin temp_filename in
o1#save backing_store_save;
close_out backing_store_save;
let backing_store_restore = open_in_bin temp_filename in
o2#restore backing_store_restore;
close_in backing_store_restore
let o = new person "john" 42 in
let o2 = new person "nobody" 0 in
transfer (o :> serializable) (o2 :> serializable);
o2#print
perl
package Person;
use Moose;
use MooseX::Storage;
with Storage('format' => 'JSON', 'io' => 'File');
has 'name' => (is => 'rw', isa => 'Str');
has 'age' => (is => 'rw', isa => 'Int');
1;
Person->new( name => 'David B.', age => 28)->store('person.json');
my $p = Person->load('person.json');
use Moose;
use MooseX::Storage;
with Storage('format' => 'JSON', 'io' => 'File');
has 'name' => (is => 'rw', isa => 'Str');
has 'age' => (is => 'rw', isa => 'Int');
1;
Person->new( name => 'David B.', age => 28)->store('person.json');
my $p = Person->load('person.json');
{
package Serializable;
use Role::Basic;
use Storable qw'store_fd retrieve_fd';
use Scalar::Util 'blessed';
use IO::Handle;
use Carp;
sub save {
my $self = shift;
my $fd = shift or croak 'Needs target file handle';
$DB::single = (1);
store_fd($self, $fd);
}
sub restore {
my $class = shift;
my $fd = shift or croak 'Needs source file handle';
my $self = retrieve_fd( $fd );
bless $self, $class
}
}
{
package Person;
use Role::Basic 'with';
use Scalar::Util 'looks_like_number';
use Carp;
with 'Serializable';
sub new {
my $class = shift;
croak 'Invalid parameters' if (@_ % 2);
%parameters = @_;
do {
croak "Missing $_" unless defined $parameters{$_}
} for qw/name age/;
croak 'Invalid age' unless looks_like_number($parameters{age});
bless \%parameters, $class
}
sub name {
$self{name}
}
sub age {
$self{age}
}
}
use IO::Handle;
my $p1 = Person->new(age => 42, name => 'Milly Fogg');
open my $fh, '+>', 'person.store';
$p1->save( $fh );
seek $fh, 0, SEEK_SET;
my $p2 = Person->restore( $fh );
package Serializable;
use Role::Basic;
use Storable qw'store_fd retrieve_fd';
use Scalar::Util 'blessed';
use IO::Handle;
use Carp;
sub save {
my $self = shift;
my $fd = shift or croak 'Needs target file handle';
$DB::single = (1);
store_fd($self, $fd);
}
sub restore {
my $class = shift;
my $fd = shift or croak 'Needs source file handle';
my $self = retrieve_fd( $fd );
bless $self, $class
}
}
{
package Person;
use Role::Basic 'with';
use Scalar::Util 'looks_like_number';
use Carp;
with 'Serializable';
sub new {
my $class = shift;
croak 'Invalid parameters' if (@_ % 2);
%parameters = @_;
do {
croak "Missing $_" unless defined $parameters{$_}
} for qw/name age/;
croak 'Invalid age' unless looks_like_number($parameters{age});
bless \%parameters, $class
}
sub name {
$self{name}
}
sub age {
$self{age}
}
}
use IO::Handle;
my $p1 = Person->new(age => 42, name => 'Milly Fogg');
open my $fh, '+>', 'person.store';
$p1->save( $fh );
seek $fh, 0, SEEK_SET;
my $p2 = Person->restore( $fh );
php
class Person implements Serializable {
private $name;
private $age;
public function __construct($name, $age) {
$this->name = $name;
$this->age = $age;
}
public function serialize() {
return serialize(array($this->name, $this->age));
}
public function unserialize($serialized) {
list($this->name, $this->age) = unserialize($serialized);
}
public function getData() {
return array($this->name, $this->age);
}
}
$obj = new Person('Gaylord Focker', 21);
file_put_contents('person.dump', serialize($obj));
$newobj = unserialize(file_get_contents('person.dump'));
var_dump($newobj->getData());
private $name;
private $age;
public function __construct($name, $age) {
$this->name = $name;
$this->age = $age;
}
public function serialize() {
return serialize(array($this->name, $this->age));
}
public function unserialize($serialized) {
list($this->name, $this->age) = unserialize($serialized);
}
public function getData() {
return array($this->name, $this->age);
}
}
$obj = new Person('Gaylord Focker', 21);
file_put_contents('person.dump', serialize($obj));
$newobj = unserialize(file_get_contents('person.dump'));
var_dump($newobj->getData());
python
import pickle
class Person:
def __init__(self, name, age):
self.name = name
self.age = age
def __str__(self):
return "Name: {name}, age: {age}".format(name=self.name, age=self.age)
person = Person("Gaylord Focker", 21)
with open("person.pickle", "wb") as outstream:
pickle.dump(person, outstream)
with open("person.pickle", "rb") as instream:
deserialized_person = pickle.load(instream)
print(deserialized_person)
class Person:
def __init__(self, name, age):
self.name = name
self.age = age
def __str__(self):
return "Name: {name}, age: {age}".format(name=self.name, age=self.age)
person = Person("Gaylord Focker", 21)
with open("person.pickle", "wb") as outstream:
pickle.dump(person, outstream)
with open("person.pickle", "rb") as instream:
deserialized_person = pickle.load(instream)
print(deserialized_person)
ruby
class Person
def initialize(name, age)
@name, @age = name, age
end
end
tom = Person.new("Tom Bones", 23)
File.open('tommy.dump', 'w+') {|f| f.write(Marshal.dump(tommy)) }
toms_clone = Marshal.load(File.read('tommy.dump'))
def initialize(name, age)
@name, @age = name, age
end
end
tom = Person.new("Tom Bones", 23)
File.open('tommy.dump', 'w+') {|f| f.write(Marshal.dump(tommy)) }
toms_clone = Marshal.load(File.read('tommy.dump'))
scala
class Person (var name: String, var age: Int) extends Serializable
val p1 = new Person("John", 21)
val output = new ByteArrayOutputStream()
val oos = new ObjectOutputStream(output)
oos.writeObject(p1)
oos.flush
oos.close
val input = new ByteArrayInputStream(output.toByteArray())
val ois = new ObjectInputStream(input)
val p2 = ois.readObject().asInstanceOf[Person]
assert(p2.name == "John")
assert(p2.age == 21)
val p1 = new Person("John", 21)
val output = new ByteArrayOutputStream()
val oos = new ObjectOutputStream(output)
oos.writeObject(p1)
oos.flush
oos.close
val input = new ByteArrayInputStream(output.toByteArray())
val ois = new ObjectInputStream(input)
val p2 = ois.readObject().asInstanceOf[Person]
assert(p2.name == "John")
assert(p2.age == 21)
