Examples

In this problem we print out hemisphere info for a City.

Given:

City	Country	Latitude	Longitude
Accra	Ghana	5.6037	-0.1870

Instructions:

Construct a City object from the given data
Print out a nice display string of the city
Print out whether or not (true/false) the is in the northern hemisphere

Hint - There is a common method that should yield a nice display string

Solution

We first find the method menu for City. We then peruse the menu and decide on:

Call static method to construct
Call method to render nice display string
Call method that tells us if city is in northern hemisphere

var city;

city = City.1fromNameCountryLatLong(
	"Accra", "Ghana", 5.6037, -0.1870);


println(city.2toString());

println("Northern Hemisphere: " + city.3isInNorthernHemisphere());

Problem

In this problem the roofing company is simply getting familiar with the project.

Given:

Label	Dimension 1	Dimension 2
Gymnasium Roof	400	200
Auditorium Roof	300	310

Instructions:

Construct objects using the three attributes for each roof
Print out each roof as a nice display string

Hint - The roofs are rectangular

Solution

We first browse the method menus and choose the Rectangle menu as it applies to our problem.

We then select these off the menu (and apply to two objects):

Call static method to construct
Call method to set given label
Call method to render nice display string

We then repeat the steps for the second object.

let gym, auditorium;


gym = Rectangle.1fromWidthHeight(400, 200);


gym.2setLabel('Gymnasium Roof');


3println(gym.toString());

auditorium = Rectangle.fromWidthHeight(300, 310);
auditorium.setLabel('Auditorium Roof');
println(auditorium.toString());

Problem

Instructions:

Construct a list of City objects
Print out nice display string of each item in the list

Hint - You may call a method that generates the list for you (if one is available).

Solution

We first find the method menu for City and choose to call these methods:

Call static method to construct list of cities
Iterate and, for each city, call method to render nice display string

let cities = City.1newSampleSet1();
for (let nextCity of cities)
	println(nextCity.2toString());

Problem

In this problem we determine if we need to think about extra safety depending on the proximity of a predicted meteor landing.

Given:
Location Description	Latitude	Longitude
NHCC	45.1	-93.4
Meteor Landing	45.3	-93.2

Instructions:

A meteor is expected to land near NHCC
A student has data structures class on campus on the day of the expected meteor
If the predicted landing is within 20 miles of the college, advise the student to wear a hard hat
Print out if a student should wear a hard hat

Solution

We first find the method menu for GeoLocation to model the given (lat, long) data. We also find the menu for ToolLib which provides a very helpful utility function.

Call static method to construct a GeoLocation
Call static method to construct a GeoLocation
Call static utility latLongDistFromTo to compute distance
Check distance vs safety threshold

Lastly, we print out the appropriate message.

//d for distance
let meteor, nhcc, d, safetyThreshold;


meteor = GeoLocation.1fromLatLong(45.1, -93.4);


nhcc = GeoLocation.2fromLatLong(45.3, -93.2);


d = ToolLib.3latLongDistFromTo(meteor, nhcc);
println('Distance to Meteor (miles): ' + d);
safetyThreshold = 20;


if (4d <= safetyThreshold)
	println('Student should wear hard hat');
else
	println('Student does not need hard hat');