• 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

      • 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

      • 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

      • 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

      • 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
}

      • 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

      • 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

      • 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

      • 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())

      • Dart

        Example of trait class in dart.
        class HasFlippers {
	String swim() {
		return 'can swim';
	}
}

class 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
}

      • 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

      • 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

      • Javascript

        Example of interface class in javascript.
        // NA

      • 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

      • 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
}

      • 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

      • 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

      • 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

      • 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

      • 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
}

      • 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

      • 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
}

      • 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
}

      • 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

      • Dart

        Example of enum class in dart.
        enum Days {
	sunday,
	monday,
	yuesday,
	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
  }
}

      • 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
	}
}