Q$1$: About Polymorphism

$5Pts$

Consider the following inheritance hierarchy.

A class 'Computer' that has:

One instance variable "name" of type String.

One instance variable "downloadSpeed" of type double giving download speed of the

network in MB$/$s$.($megabytes$/$second$)$

A subclass 'PersonalComputer' that:

has one additional private instance variable "connectionTime" of type double

indicating the number of seconds the computer was connected.

one method "totalMegaBytesDownloaded $()"$ calculating the Total megabytes

downloaded by mutiplying the downloadSpeed by connectionTime.

A Desktop class which is a subclass of PersonalComputer that :

has an additional variable "goodCondition" of type boolean.

overrides totalMegaBytesDownloaded $()$ method as follows:

if goodCondition $=$ true, the total MB downloaded are increased by $20\%$

if goodCondition false, the total MB downloaded are reduced by $20\%$

A Laptop class which is a subclass of PersonalComputer that:

as an additional variable "wirelessAva$1$lable" of type boolean.

overrides totalMegaBytesDownloaded$()$ method as follows:

if wirelessAvailable $=$ true, the total MB downloaded is $3000MB.$

if wirelessAvailable $=$ false, the total MB downloaded is zero.

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Provide suitable constructor$($s$),$ accessor$/$mutator methods and a tostring$()$ method for

all the classes. Write an application class that generates an array of type Computer of $6$

objects from either a Desktop or a Laptop. For example

Computer e$1=$ new LapTop $("$Toshiba$",56\mathrm{.}5,100,$ true$)$;

Print the following information about your array:

the total number of desktops in your collection

the total number of laptops in your collection

the total MB downloaded by all desktops in your collection

the total MB downloaded by all laptops in your collection.

the average MB downloaded by all desktops in your collection.

the average MB downloaded by all laptops in your collection.

the number of desktops in good condition.

the number of laptops with wireless not available.