Class declaration syntax in Ruby

Introduction

Classes help you organize code by grouping related data and actions together.

When you want to model real-world things like a car or a person in your program.

When you need to create multiple similar objects with shared behavior.

When you want to keep your code clean and easy to understand by grouping related methods.

When you want to reuse code by creating new classes based on existing ones.

Syntax

Ruby

class ClassName
  # code goes here
end

Class names start with a capital letter.

Use end to close the class definition.

Examples

This creates an empty class named Dog.

Ruby

class Dog
end

This class Person has a method greet that prints a message.

Ruby

class Person
  def greet
    puts "Hello!"
  end
end

This class Car has an initialize method to set up new objects with make and model.

Ruby

class Car
  def initialize(make, model)
    @make = make
    @model = model
  end
end

Sample Program

This program defines a class Animal with a method speak. Then it creates an object my_pet and calls speak to print a message.

Ruby

class Animal
  def speak
    puts "I make a sound"
  end
end

my_pet = Animal.new
my_pet.speak

Important Notes

Remember to use new to create an object from a class.

Instance variables start with @ and belong to each object.

Summary

Classes group related data and methods.

Class names start with a capital letter and end with end.

Use new to create objects from classes.