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Classes

A class in programming is like a group of people. For example, if you have a group of friends, each person in the group is called a "friend". In programming, we call each person in the group a "class". Just like your friends might all have different names and personalities, classes can also have different names and qualities. So when you write code, you can create different classes with different names and abilities to do things.

Object ^Classes

Javascript

Example of object class in javascript.

class Person {
	constructor(name, age) {
		this.name = name;
		this.age = age;
	}

	greet() {
		console.log('Hello my name is ' + this.name);
	}
}

var human = new Person('John', 36);

console.log(human.name); // John
console.log(human.age); // 36
human.greet(); // Hello my name is John

Dart

Example of object class in dart.

class Person {
  String name;
  int age;

  Person(this.name, this.age);

  void greet() {
	print('Hello my name is ' + this.name);
  }
}

void main() {
  var human = new Person('John', 36);

  print(human.name); // John
  print(human.age); // 36
  human.greet(); // Hello my name is John
}

D

Example of object class in d.

import std.stdio : write, writeln;
import std.string;

class Person {
	string name;
	int age;

	this(string name, int age) {
		this.name = name;
		this.age = age;
	}

	void greet() {
		write("Hello my name is ", this.name);
	}
}

void main()
{
	Person human = new Person("John", 36);

	writeln(human.name); // John
	writeln(human.age); // 36
	human.greet(); // Hello my name is John
}

Php

Example of object class in php.

<?php
class Person {
	public $name, $age;

	function __construct($name, $age) {
		$this->name = $name;
		$this->age = $age;
	}

	public function greet() {
		print('Hello my name is ' . $this->name);
	}
}

$human = new Person('John', 36);

print($human->name); // John
print($human->age); // 36
$human->greet(); // Hello my name is John

Python

Example of object class in python.

class Person:
	def __init__(self, name, age):
		self.name = name
		self.age = age

	def greet(self):
		print('Hello my name is ' + self.name)


human = Person('John', 36)

print(human.name)  # John
print(human.age)  # 36
human.greet()  # Hello my name is John

Go

Example of object class in go.

package main

import "fmt"

type Person struct {
	name string
	age  int
}

func (p Person) greet() {
	fmt.Println("Hello my name is " + p.name)
}

func main() {
	var human = Person{"John", 36}

	fmt.Println(human.name) // John
	fmt.Println(human.age)  // 36
	human.greet()		   // Hello my name is John
}

Trait ^Classes

Javascript

Example of trait class in javascript.

const HasFlippers = {
	swim: function () {
		return 'can swim';
	}
};

const HasFeathers = {
	fly: function () {
		return 'can fly';
	}
};

class Duck { }

Object.assign(Duck.prototype, HasFlippers, HasFeathers);

class Seal { }

Object.assign(Seal.prototype, HasFlippers);

var a = new Duck();
console.log(a.swim()); // can swim
console.log(a.fly()); // can fly

var b = new Seal();
console.log(b.swim()); // can swim

Dart

Example of trait class in dart.

mixin HasFlippers {
  String swim() {
	return 'can swim';
  }
}

mixin HasFeathers {
  String fly() {
	return 'can fly';
  }
}

class Duck with HasFlippers, HasFeathers {}

class Seal with HasFlippers {}

void main() {
  var a = new Duck();
  print(a.swim()); // can swim
  print(a.fly()); // can fly

  var b = new Seal();
  print(b.swim()); // can swim
}

D

Example of trait class in d.

import std.stdio : writeln;
import std.string;

mixin template HasFlippers() {
	string swim() {
		return "can swim";
	}
}

mixin template HasFeathers() {
	string fly() {
		return "can fly";
	}
}

class Duck {
	mixin HasFlippers;
	mixin HasFeathers;
}

class Seal {
	mixin HasFlippers;
}

void main() {
	Duck a = new Duck();
	writeln(a.swim()); // can swim
	writeln(a.fly()); // can fly

	Seal b = new Seal();
	writeln(b.swim()); // can swim
}

Php

Example of trait class in php.

<?php
trait HasFlippers
{
	public function swim()
	{
		return 'can swim';
	}
}

trait HasFeathers
{
	public function fly()
	{
		return 'can fly';
	}
}

class Duck
{
	use HasFlippers, HasFeathers;
}

class Seal
{
	use HasFlippers;
}

$a = new Duck();
print($a->swim()); // can swim 
print($a->fly()); // can fly 

$b = new Seal();
print($b->swim()); // can swim

Python

Example of trait class in python.

import math


class HasFlippers(object):
	def swim(self):
		return 'can swim'


class HasFeathers(object):
	def fly(self):
		return 'can fly'


class Duck(HasFlippers, HasFeathers):
	pass


class Seal(HasFlippers):
	pass


a = Duck()
print(a.swim())
print(a.fly())

b = Seal()
print(b.swim())

Go

Example of trait class in go.

package main

import "fmt"

type HasFlippers string

type HasFeathers string

func (h HasFlippers) swim() string {
	return "can swim"
}

func (h HasFeathers) fly() string {
	return "can fly"
}

type Duck struct {
	HasFlippers
	HasFeathers
}

type Seal struct {
	HasFlippers
}

func main() {
	var a Duck
	fmt.Println(a.swim())
	fmt.Println(a.fly())

	var b Seal
	fmt.Println(b.swim())
}

Interface ^Classes

Javascript
Example of interface class in javascript.
```
// NA
```

Dart

Example of interface class in dart.

import "dart:math" show pi;

abstract class Shape {
  double area();
}

class Rectangle implements Shape {
  double width;
  double height;

  Rectangle(this.width, this.height);

  double area(){
	return this.width * this.height;
  }
}

class Circle implements Shape {
  double radius;

  Circle(this.radius);

  double area(){
	return pi * this.radius * this.radius;
  }
}

void main() {
  Rectangle a = new Rectangle(3, 5);
  Circle b = new Circle(4);

  print("area of a is ${a.area().toStringAsPrecision(8)}");  // area of a is 15.000000
  print("area of b is ${b.area().toStringAsPrecision(8)}");  // area of b is 50.265482
}

D

Example of interface class in d.

import std.stdio : writefln;
import std.math.constants;

interface Shape {
	double area();
}

class Rectangle : Shape {
	double width;
	double height;

	this(double width, double height) {
		this.width = width;
		this.height = height;
	}

	double area() {
		return this.width * this.height;
	}
}

class Circle : Shape {
	double radius;

	this(double radius) {
		this.radius = radius;
	}

	double area() {
		return PI * this.radius * this.radius;
	}
}

void main()
{
	Rectangle a = new Rectangle(3, 5);
	Circle b = new Circle(4);

	writefln("area of a is %f", a.area());  // area of a is 15.000000
	writefln("area of b is %f", b.area());  // area of b is 50.265482
}

Php

Example of interface class in php.

<?php
interface Shape {
	public function area();
}

class Rectangle implements Shape {
	public $width, $height;

	function __construct($width, $height){
		$this->width = $width;
		$this->height = $height;
	}

	public function area()
	{
		return $this->width * $this->height;
	}
}

class Circle implements Shape {
	public $radius;

	function __construct($radius){
		$this->radius = $radius;
	}

	public function area()
	{
		return pi() * $this->radius * $this->radius;
	}
}

$a = new Rectangle(3, 5);
$b = new Circle(4);

printf('area of a is %f', $a->area()); // area of a is 15.000000
printf('area of b is %f', $b->area()); // area of b is 50.265482

Python

Example of interface class in python.

import math


class Shape:
	def area():
		pass


class Rectangle(Shape):
	def __init__(self, width, height):
		self.width = width
		self.height = height

	def area(self):
		return self.width * self.height


class Circle(Shape):
	def __init__(self, radius):
		self.radius = radius

	def area(self):
		return math.pi * self.radius * self.radius


a = Rectangle(width=3, height=5)
b = Circle(radius=4)

print('area of a is {:f}'.format(a.area()))  # area of a is 15.000000
print('area of b is {:f}'.format(b.area()))  # area of b is 50.265482

Go

Example of interface class in go.

package main

import (
	"fmt"
	"math"
)

type Shape interface {
	Area() float64
}

type Rectangle struct {
	width  float64
	height float64
}

type Circle struct {
	radius float64
}

func (r Rectangle) Area() float64 {
	return r.width * r.height
}

func (c Circle) Area() float64 {
	return math.Pi * c.radius * c.radius
}

func main() {
	var a, b Shape
	
	a = Rectangle{width: 3, height: 5}
	b = Circle{radius: 4}

	fmt.Printf("area of a is %f", a.Area()) // area of a is 15.000000
	fmt.Printf("area of b is %f", b.Area()) // area of b is 50.265482
}

Struct ^Classes

Javascript

Example of struct class in javascript.

class Person {
	constructor(name, age) {
		this.name = name;
		this.age = age;
	}
}

const human = new Person('John', 36);

console.log(human.name); // John
console.log(human.age); // 36

Dart

Example of struct class in dart.

class Person {
  String name;
  int age;

  Person(this.name, this.age);
}

void main() {
  var human = new Person('John', 36);

  print(human.name); // John
  print(human.age); // 36
}

D

Example of struct class in d.

import std.stdio : writeln;
import std.string;

struct Person {
	string name;
	int age;

	this(string name, int age) {
		this.name = name;
		this.age = age;
	}
}

void main()
{
	Person human = Person("John", 36);

	writeln(human.name); // John
	writeln(human.age); // 36
}

Php

Example of struct class in php.

<?php
class Person
{
	public string $name;
	public int $age;

	function __construct(string $name, int $age)
	{
		$this->name = $name;
		$this->age = $age;
	}
}

$human = new Person('John', 36);

print($human->name); // John
print($human->age); // 36

Python

Example of struct class in python.

from typing import NamedTuple

class Person(NamedTuple):
	name: str
	age: int


human = Person(name='John', age=36)

print(human.name)  # John
print(human.age)  # 36

Go

Example of struct class in go.

package main

import "fmt"

type Person struct {
	name string
	age  int
}

func main() {
	var human = Person{"John", 36}

	fmt.Println(human.name) // John
	fmt.Println(human.age)  // 36
}

Enum ^Classes

Javascript

Example of enum class in javascript.

const Days = {
	Sunday: 0,
	Monday: 1,
	Tuesday: 2,
	Wednesday: 3,
	Thursday: 4,
	Friday: 5,
	Saturday: 6
};

var day = 4;

if (day == Days.Saturday || day == Days.Sunday) {
	console.log('a weekend');
} else {
	console.log('a weekday'); // a weekday
}

Dart

Example of enum class in dart.

enum Days {
	sunday,
	monday,
	tuesday,
	wednesday,
	thursday,
	friday,
	saturday
}

void main() {
	var day = 4;

	if (day == Days.saturday.index || day == Days.sunday.index) {
	print('a weekend');
	} else {
	print('a weekday'); // a weekday
	}
}

D

Example of enum class in d.

import std.stdio : write;

enum Days {
	Sunday,
	Monday,
	Tuesday,
	Wednesday,
	Thursday,
	Friday,
	Saturday
}

void main()
{
	int day = 4;

	if (day == Days.Saturday || day == Days.Sunday) {
		write("a weekend");
	} else {
		write("a weekday"); // a weekday
	}
}

Php

Example of enum class in php.

<?php
enum Days: int
{
	case Sunday = 0;
	case Monday = 1;
	case Tuesday = 2;
	case Wednesday = 3;
	case Thursday = 4;
	case Friday = 5;
	case Saturday = 6;
}

$day = 4;

if ($day == Days::Saturday->value || $day == Days::Sunday->value) {
	print('a weekend');
} else {
	print('a weekday'); // a weekday
}

Python

Example of enum class in python.

from enum import Enum

class Days:
	Sunday = 0
	Monday = 1
	Tuesday = 2
	Wednesday = 3
	Thursday = 4
	Friday = 5
	Saturday = 6

day = 4;

if day == Days.Saturday or day == Days.Sunday :
	print('a weekend');
else:
	print('a weekday'); # a weekday

Go

Example of enum class in go.

package main

import "fmt"

const (
	Sunday	int = 0
	Monday	int = 1
	Tuesday   int = 2
	Wednesday int = 3
	Thursday  int = 4
	Friday	int = 5
	Saturday  int = 6
)

func main() {
	var day int = 4

	if day == Saturday || day == Sunday {
		fmt.Println("a weekend")
	} else {
		fmt.Println("a weekday") // a weekday
	}
}

Classes

Object Classes

Javascript

Example of object class in javascript.

Dart

Example of object class in dart.

D

Example of object class in d.

Php

Example of object class in php.

Python

Example of object class in python.

Go

Example of object class in go.

Trait Classes

Javascript

Example of trait class in javascript.

Dart

Example of trait class in dart.

D

Example of trait class in d.

Php

Example of trait class in php.

Python

Example of trait class in python.

Go

Example of trait class in go.

Interface Classes

Javascript

Example of interface class in javascript.

Dart

Example of interface class in dart.

D

Example of interface class in d.

Php

Example of interface class in php.

Python

Example of interface class in python.

Go

Example of interface class in go.

Struct Classes

Javascript

Example of struct class in javascript.

Dart

Example of struct class in dart.

D

Example of struct class in d.

Php

Example of struct class in php.

Python

Example of struct class in python.

Go

Example of struct class in go.

Enum Classes

Javascript

Example of enum class in javascript.

Dart

Example of enum class in dart.

D

Example of enum class in d.

Php

Example of enum class in php.

Python

Example of enum class in python.

Go

Example of enum class in go.

Object ^Classes

Trait ^Classes

Interface ^Classes

Struct ^Classes

Enum ^Classes