• Gain proficiency instantiating a class
• Gain ability to discern when to implement attr_accessor, attr_reader, and attr_writer
• Gain ability to discern when to define your own attr_reader (getter) and attr_writer (setter) methods

To practice object oriented programming (OOP), you're going to create a Computer class. Each instance of the Computer class will have the ability to:

• report its specs
• store a file
• delete a file
• upgrade memory

In the instructions below (and in other labs), you'll see this notation used to represent instance methods and class methods:

• ClassName#method_name: represents an instance method that can be called on the class
• ClassName.method_name: represents a class method that can be called on the class

For example, Computer#brand is an example of an instance method, that we can call on an instance of a class:

class Computer
  def brand
    @brand
  end
end

We can also define this particular instance method using a macro (which creates the getter method for us):

class Computer
  attr_reader :brand
end

Computer.new is an example of a class method (remember, to create a new instance of the class, we call ClassName.new, which then calls the instance method ClassName#initialize).

Create a Computer class with the following behavior:

• Computer.new(brand, model): takes arguments of a brand and model and saves them to the object. The computer's model and brand should not be able to change after initialization. When a new computer is created, it should have the following attributes in addition to its brand and model (saved to instance variables):

  • @memory_GB with an initial value of 8
  • @storage_free with an initial value of 1000

• [] Computer#brand: gets the computer's brand.

• []Computer#model: gets the computer's model.

• [] Computer#memory_GB: gets the amount of RAM in a computer's bank memory.

• [] Computer#memory_GB=(value): sets the value of the memory to a new amount.

• [] Computer#storage_free: gets the size of the computer's storage in gigabytes.

• [] Computer#storage_free=(value): sets the value of the computer's free storage. The maximum value allowed is 1000, and the minimum value allowed is 0.

• [] Computer#upgrade_memory(RAM): takes a hash ({model: String, size: Integer}) and adds the size of the RAM to the computer's memory

• [] Computer#disk_full?(file_size): receives a file_size number and returns true if the free storage space is less than the file size; otherwise returns false.

• [] Computer#save_file(file): given a file hash ({name: String, size: Number}), this method will first use a helper method to check whether the disk has enough space to save the file. If there is enough space, reduce the value of storage_free by the file size and return the string "#{file[:name]} has been saved!", but if there is not enough space, return the string "There is not enough space on disk to save #{file[:name]}."

• []Computer#delete_file(file): given a file hash ({name: String, size: Number}), make the appropriate adjustment to the free storage size and return a string confirming that the file has been deleted which includes the file's name.

• []Computer#specs: returns a string which includes both the current memory and free storage, both in gigabytes.