Shortest possible explanation , with a demonstration
Local variables are accesible only in the local scope i.e. method or function e.g.
class Book
def initialize
name = "Harry Potter and the Philosopher's Stone"
end
def print_name
puts name # this will fail with a Variable Not Found error
end
endThe local variable name above is not accesible in the print_name method.
To get a variable whose scope is the entire object instance, we need an instance variable
class Book
def initialize
@name = "Harry Potter and the Philosopher's Stone"
end
def print_name
puts @name # this will work and print out the right value
end
end